Now thou has loved me one whole day
Tomorrow when you leav'st, what wilt thou say?
Wilt thou then antedate some new-made vow?
Or say that now
We are not just those persons which we were?
Or, that oaths made in reverential fear
Of Love, and his wrath, any may forswear?
Or, as true deaths true marriages untie
“Or”, asks the man, “will you be the cliche and say oh, lover, we are just not the people we used be, that was not us, we are different people now that the night has ended?” 
 Donne seems to be asking his girl if she’s going to claim that they  aren’t  the two people who just spent the entire day loving each other – because that seems to be the only way her behaviour can be explained. 
 He seems to be saying, “Yesterday John Donne and [insert 17th century wench’s name here] said they loved each other and only had eyes for one another —- are we not those two very same people?”
Womans Constancy