Grounds for divorce vary widely from country to country. Marriage may be seen as a contract, a status, or a combination of these. Where it is seen as a contract, the refusal or inability of one spouse to perform the obligations stipulated in the contract may constitute a ground for divorce for the other spouse. In contrast, in some countries (such as Sweden, Finland, Australia, New Zealand), divorce is purely no fault. Many jurisdictions offer both the option of a no fault divorce as well as an at fault divorce. This is the case, for example, in many US states (see Grounds for divorce (United States)).

Though divorce laws vary between jurisdictions, there are two basic approaches to divorce: fault based and no-fault based. However, even in some jurisdictions that do not require a party to claim fault of their partner, a court may still take into account the behavior of the parties when dividing property, debts, evaluating custody, shared care arrangements and support. In some jurisdictions one spouse may be forced to pay the attorney's fees of another spouse.

Laws vary as to the waiting period before a divorce is effective. Also, residency requirements vary. However, issues of division of property are typically determined by the law of the jurisdiction in which the property is located.

In Europe, divorce laws differ from country to country, reflecting differing legal and cultural traditions. In some countries, particularly (but not only) in some former communist countries, divorce can be obtained only on one single general ground of "irretrievable breakdown of the marriage" (or a similar formulation). Yet, what constitutes such a "breakdown" of the marriage is interpreted very differently from jurisdiction to jurisdiction, ranging from very liberal interpretations (e.g. Netherlands) to quite restrictive ones (e.g., in Poland, there must be an "irretrievable and complete disintegration of matrimonial life," but there are many restrictions to granting a divorce). Separation constitutes a ground of divorce in some European countries (in Germany, e.g., a divorce is granted on the basis of a 1-year separation if both spouses consent, or 3-year separation if only one spouse consents). Note that "separation" does not necessarily mean separate residences – in some jurisdictions, living in the same household but leading a separate life (e.g., eating, sleeping, socializing, etc. separately) is sufficient to constitute de facto separation; this is explicitly stated, e.g., in the family laws of Latvia.

Divorce laws are not static; they often change reflecting evolving social norms of societies. In the 21st century, many European countries have made changes to their divorce laws, in particular by reducing the length of the necessary periods of separation, e.g., Scotland in 2006 (1 or 2 years from the previous 2 or 5 years); France in 2005 (2 years from the previous 6 years), Switzerland in 2005 (2 years from the previous 4 years), Greece in 2008 (two years from the previous four years). Some countries have completely overhauled their divorce laws, such as Spain in 2005, and Portugal in 2008. A new divorce law also came into force in September 2007 in Belgium, creating a new system that is primarily no-fault. Bulgaria also modified its divorce regulations in 2009. Also in Italy, new laws came into force in 2014 and 2015 with significant changes in Italian law in matter of divorce: apart from shortening of the period of obligatory separation (6 months or 1 year from the previous 3 years), are allowed other forms of getting a divorce – as an alternative to court proceedings, i.e. the negotiations with the participation of an advocate or agreement made before the registrar of Public Registry Office.Austria, instead, is a European country where the divorce law still remains conservative.

The liberalization of divorce laws is not without opposition, particularly in the United States. Indeed, in the US, certain conservative and religious organizations are lobbying for laws which restrict divorce. In 2011, in the US, the Coalition for Divorce Reform was established, describing itself as an organization "dedicated to supporting efforts to reduce unnecessary divorce and promote healthy marriages."

Types

In some jurisdictions, the courts will seldom apply principles of fault, but might willingly hold a party liable for a breach of a fiduciary duty to his or her spouse (for example, see Family Code Sections 720 and 1100 of the California Family Code). Grounds for divorce differs from state to state in the U.S. Some states have no-fault divorce; some states require a declaration of fault on the part of one partner or both; some states allow either method.

In most jurisdictions, a divorce must be certified (or ordered by a Judge) by a court of law to come into effect. The terms of the divorce are usually determined by the courts, though they may take into account prenuptial agreements or post-nuptial agreements, or simply ratify terms that the spouses may have agreed to privately (this is not true in the United States, where agreements related to the marriage typically have to be rendered in writing to be enforceable). In absence of agreement, a contested divorce may be stressful to the spouses.

In some other countries, when the spouses agree to divorce and to the terms of the divorce, it can be certified by a non-judiciary administrative entity. The effect of a divorce is that both parties are free to marry again if a filing in an appellate court does not overturn the decision.

Contested divorce

Contested divorces mean that one of several issues are required to be heard by a judge at trial level—this is more expensive, and the parties will have to pay for a lawyer's time and preparation. In such a divorce the spouses are not able to agree on issues for instance child custody and division of marital assets. In such situations, the litigation process takes longer to conclude. The judge controls the outcome of the case. Less adversarial approaches to divorce settlements have recently emerged, such as mediation and collaborative divorce settlement, which negotiate mutually acceptable resolution to conflicts. This principle in the United States is called 'Alternative Dispute Resolution' and has gained popularity.

At-fault divorce

Before the late 1960s, nearly all countries that permitted divorce required proof by one party that the other party had committed an act incompatible to the marriage. This was termed "grounds" for divorce (popularly called "fault") and was the only way to terminate a marriage. Most jurisdictions around the world still require such proof of fault. In the United States, no-fault divorce is available in all 50 states, as is the case with Australia, New Zealand, Canada and other Western countries.

Fault-based divorces can be contested; evaluation of offenses may involve allegations of collusion of the parties (working together to get the divorce), or condonation (approving the offense), connivance (tricking someone into committing an offense), or provocation by the other party. Contested fault divorces can be expensive, and not usually practical as eventually most divorces are granted. Comparative rectitude is a doctrine used to determine which spouse is more at fault when both spouses are guilty of breaches.

The grounds for a divorce which a party could raise and need to prove included 'desertion,' 'abandonment,' 'cruelty,' or 'adultery.' The requirement of proving a ground was revised (and withdrawn) by the terms of 'no-fault' statutes, which became popular in many Western countries in the late 1960s and early 1970s. In 'no-fault' jurisdictions divorce can be obtained either on a simple allegation of 'irreconcilable differences,' 'irretrievable break-down', or 'incompatibility' with respect to the marriage relationship, or on the ground of de facto separation.

Summary divorce

A summary (or simple) divorce, available in some jurisdictions, is used when spouses meet certain eligibility requirements or can agree on key issues beforehand.

Key factors:

• Short duration of marriage (less than five years)
• Absence of children (or, in some jurisdictions, prior allocation of child custody and of child-support direction and amount)
• Absence or minimal value of real property at issue and any associated encumbrances such as mortgages
• Absence of agreed-as-marital property above a given value threshold (around $35,000 not including vehicles)
• Absence, with respect to each spouse, of claims to personal property above a given value threshold, typically the same as that for total marital property, with such claims including claims to exclusive previous ownership of property described by the other spouse as marital

No-fault divorce

Some Western jurisdictions have a no-fault divorce system, which requires no allegation or proof of fault of either party. The barest of assertions suffice. For example, in countries that require "irretrievable breakdown", the mere assertion that the marriage has broken down will satisfy the judicial officer. In other jurisdictions requiring irreconcilable differences, the mere allegation that the marriage has been irreparable by these differences is enough for granting a divorce. Courts will not inquire into facts. A "yes" is enough, even if the other party vehemently says "no".

The application can be made by either party or by both parties jointly.

In jurisdictions adopting the 'no-fault' principle regarding whether to grant a divorce, some courts may still take into account the fault of the parties when determining some aspects of the content of the divorce decree, e.g., its terms for the division of property and debts and the existence and, if applicable, the amount of spousal support. Provisions related to child custody are determined using a different fundamental standard, that of the child's or children's best interests; while some behaviors that may constitute marital fault (e.g., violence, cruelty, endangerment, neglect, or substance abuse) may also qualify as factors to be considered when determining child custody, they do so for the independent reason that they provide evidence as to what arrangement is in the child's or children's best interests going forward.

Uncontested divorce

It is estimated that upwards of 95% of divorces in the U.S. are "uncontested", because the two parties are able to come to an agreement (either with or without lawyers/mediators/collaborative counsel) about the property, children, and support issues. When the parties can agree and present the court with a fair and equitable agreement, approval of the divorce is almost guaranteed. If the two parties cannot come to an agreement, they may ask the court to decide how to split property and deal with the custody of their children. Though this may be necessary, the courts would prefer parties come to an agreement prior to entering court.

Where the issues are not complex and the parties are cooperative, a settlement often can be directly negotiated between them. In the majority of cases, forms are acquired from their respective state websites and a filing fee is paid to the state. Most U.S. states charge between $175 and $350 for a simple divorce filing. Collaborative divorce and mediated divorce are considered uncontested divorces.

Because of additional requirements that must be met, most military divorces are typically uncontested.

In the United States, many state court systems are experiencing an increasing proportion of pro se (i.e., litigants represent themselves without a lawyer) in divorce cases. In San Diego, for example, the number of divorce filings involving at least one self-representing litigant rose from 46% in 1992 to 77% in 2000, and in Florida from 66% in 1999 to 73% in 2001. Urban courts in California report that approximately 80% of the new divorce filings are filed pro se.

Collaborative divorce

Collaborative divorce is a method for divorcing couples to come to agreement on divorce issues. In a collaborative divorce, the parties negotiate an agreed resolution with the assistance of attorneys who are trained in the collaborative divorce process and in mediation and often with the assistance of a neutral financial specialist or divorce coaches. The parties are empowered to make their own decisions based on their own needs and interests, but with complete information and full professional support.

Once the collaborative divorce starts, the lawyers are disqualified from representing the parties in a contested legal proceeding, should the collaborative law process end prematurely. Most attorneys who practice collaborative divorce claim that it can be more cost-effective than other divorce methods, e.g., going to court. Expense, they say, has to be looked at under the headings of financial and emotional. Also, the experience of working collaboratively tends to improve communication between the parties, particularly when collaborative coaches are involved, and the possibility of going back to court post-separation or divorce is minimized. In the course of the collaboration, should