Private international law

Conflict of laws or private international law (both terms are used interchangeably) concerns relations across different legal jurisdictions between persons, and sometimes also companies, corporations and other legal entities.

Courts faced with a choice of law issue have a two-stage process:

In divorce cases, when a court is attempting to distribute marital property, if the divorcing couple is local and the property is local, then the court applies its domestic law lex fori. The case becomes more complicated if foreign elements are thrown into the mix, such as when the place of marriage is different from the territory where divorce was filed; when the parties' nationalities and residences do not match; when there is property in a foreign jurisdiction; or when the parties have changed residence several times during the marriage.

Whereas commercial agreements or prenuptial agreements generally do not require legal formalities to be observed, when married couples enter a property agreement (agreement for the division of property at the termination of the marriage), stringent requirements are imposed, including notarization, witnesses, special acknowledgment forms. In some countries, these must be filed (or docketed) with a domestic court, and the terms must be "so ordered" by a judge. This is done in order to ensure that no undue influence or oppression has been exerted by one spouse against the other. Upon presenting a property agreement between spouses to a court of divorce, that court will generally assure itself of the following factors: signatures, legal formalities, intent, later intent, free will, lack of oppression, reasonableness and fairness, consideration, performance, reliance, later repudiation in writing or by conduct, and whichever other concepts of contractual bargaining apply in the context.

Unlike marriage which has an international recognised legal status, there are no international treaties on recognition of unmarried couple's legal status. If an unmarried couple change residence to different countries, then the local law on where the couple is last domiciled is applied to them. This covers legal status of the relationship, rights, obligations, and all worldwide movable and immovable property. To otherwise interpret the law would mean if the unmarried couple had assets in several different countries, they would then need separate legal cases in each country to resolve all their movable and immovable property.

In the absence of a valid and enforceable agreement for an unmarried couple, here’s how the conflict of law rules work:

Many contracts and other forms of legally binding agreement include a jurisdiction or arbitration clause specifying the parties' choice of venue for any litigation (called a forum selection clause). Then, choice of law clauses may specify which laws the court or tribunal should apply to each aspect of the dispute. This matches the substantive policy of freedom of contract. Judges have accepted that the principle of party autonomy allows the parties to select the law most appropriate to their transaction. This judicial acceptance of subjective intent excludes the traditional reliance on objective connecting factors; it also harms consumers as vendors often impose one-sided contractual terms selecting a venue far from the buyer's home or workplace.

...
Wikipedia