My understanding of the view that the heart has to stop beating for the person to be considered dead, is that it requires a few factors simultaneously:
- No heart beat
- No breathing
- Doctors saying that those functions cannot be revived
As long as any one of those three are in place, the person is not considered Halachicly dead.
Not remembering where I read that, as it has been a while.
Therefore, if he is revived by the doctors after the first two have happened, he was never dead, and it is considered that he lived the whole time, uninterrupted.
I have seen some discussions around bonified Techiyas HaMeisim. In that case, the marriage is dissolved, I believe was the conclusion (with all the attendant considerations). But that has nothing to do with Halachic death, Techiyas HaMeisim is a different category (see here and here).