*cracks fingers* Oh, I live for those niche questions.
Ok, so first you have to forget all that rap about “till death do us part” ; this is the religious vision of marriage and it has nothing to do with marital status. You have to look to the very legal nature of marriage, which is an institutional contract. In its purest form, marriage is about forming a legal bound with someone, to which your state attaches certain rights, privileges and duties. So, like all contracts, it can be undone two ways : by the will of the co-contractors (that’s divorce) or by invalidation, i.e. one condition for this contract to be legal is revealed to be untrue. For example, if you’re in a country that doesn’t allow polygamy and it is revealed you’ve contracted a second marriage, this marriage will be declared null and void.
Now for the case at hand, the “condition” is whether or not you need to be alive to be married. Obviously it is implied by every legal definition of marriage that you need to be alive to be wed. So, a marriage contract ends when one of the contractors dies, because simply speaking, the contract ceases to exist as its object no longer qualifies. But IF someone came back to life, that’s another situation entirely. There are chances law will not accept that you went from death to life, so it will likely have to consider that you were alive the whole time. So the question becomes : can a marriage that had come to an end because of the death of one of the co-contractors be legally revived without the need to re-marry ?
Interestingly, contrary to what you might think this is not a hypothetical case. Obviously people don’t jump out of their graves yet, but we still have a handful of cases every year in which this question appears : in the case of long-time disappearances. See, law is adamant to maintaining a person’s legal existence until there is absolute proof this person is dead, precisely because legally reviving a person is a bureaucratic nightmare. In most cases, there is a body, so no problem. But when there isn’t a body, what can you do ? There’s always a chance the person might reappear so they’re going to try very hard to maintain a possibility for them to be alive : instead of declaring the person dead, they’ll going to declare them “presumed dead”. If the person disappeared in dangerous circumstances (there was a plane crash or a flood), the state will agree to grant that status pretty quickly. But if the person simply vanished one day, you’re going to have to wait for over 10 years before this person goes from “missing” to “presumed dead”. Why agree to declare them dead at all ? Well, so successions can be opened, or people can remarry, for that matter. In the majority of cases, when someone has been gone this long, they’re either really dead or will never resurface.
BUT, believe it or not, there are a few cases each year in which a person who was been gone for 10, 20 years will come back like nothing happened. So this person was legally presumed dead. But since this is but a presumption, it means it will shatter in front of contrary evidence. However, all the legal elements of their life have been sorted, sometimes for good : if their house has been sold, and there are people living in it, you cannot kick them out so this person gets their house back. So the state is going to have to go through every legal element of the person’s life and try to preserve and compensate as much as possible. For example, if a succession they should have been a part of was opened and closed (if one of their parents died for example), it will be reopened and the person will receive as similar a part as the one they should have received as possible. If their house has been sold, they will receive monetary compensation.
Now, as for marriages. There’s a distinction in law between two types of contracts : intuitu personae and non intuitu personae. Contract that are formed intuitu personae are contracts in which the identity of at least one of the contractors is a deciding factor in forming the contract. Typically, a sale is non intuitu personae : the clerk doesn’t care that you personally bought that bag of crisps, they’ll sell it to anyone who has money. Marriage, on the other hand, is the purest example of a contract intuitu personae : your partner is marrying you, personally, and would not marry someone else. In the case someone who had been presumed dead comes back, the state will typically restore their right in the contracts non intuitu personae, but they’ll consider the contracts intuitu personae, if they have been declared void, will remain that way. So, if your house has been sold, you will get your share of the money, but if your husband/wife remarried, this new marriage will not be declared null as polygamous : your marriage has been declared over when you were presumed dead, and this contract cannot be revived because it is intuitu personae. Your partner chose to marry you back then, but the state cannot force them to remarry you automatically because marriage hinges of both contractors’ personality and identity.
So obviously this situation is a little different because the person had presumed dead, not declared dead, as it was the case with Laura since she left a body, but I think if the state will agree to consider a marriage over when someone is presumed dead, they’ll agree even more when someone was declared dead. So my final guess is, no, if you were declared dead and come back to life, your marriage doesn’t exist anymore. If you want it to exist again, you’ll have to be restored in your legal existence and then remarry.