Is there not a timeliness factor missing from the criteria or is Isaac asking "If someone proposes marriage via Manifold, will the couple in question instantaneously and immediately break up?" As Isaac has pointed out the point in time of the proposal is a specific point in time and not any time after the proposal.

Otherwise it seems like the question might need to add some additional constraints... If a marriage proposal, made via Manifold, is accepted what are the odds that the couple is still together after X [days|months|years]?

Or
If a marriage proposal is made via Manifold what are the odds that the couple is still together after the creation datetime of the proposal market?

@ShitakiIntaki Good point, added "2 weeks" as the time frame.

Is this question about the first non-fraudulent proposal?

@Yev Yeah, the first one.

How long do they have to stay together?

@MartinRandall Long enough that it doesn't seem like the proposal was the cause of the breakup.

what if they weren't together beforehand? I could propose marriage to you via Manifold, which would resolve my market. But we weren't a couple beforehand. "n/a", I suppose?

@CarsonGale I'll ignore fraudulent proposals.