When does a marriage contract come into existence?

Standard answer: depends on the state, in the United States of America. Elsewhere, well, you are just going to have to ask a specific question. Sort of rule: The state decides when marriage is contracted. Not the people who are doing it, until later. Their input has something to do with the decision, but really it's what it looks like in the eyes of other people, all out there. For sure, a marriage contract is totally unrelated to having intercourse or something like it. It's call a contract, and it is a contract. (silly little Word: consumation: this got ditched about about as fast as the Nicien Council of ?325) Check out what a contract is. It's not just friendly fornication.