Identity may be continuous, but it is not unchanging. You are not the person you were back then and are not required to be bound by their precommitments. No more than by someone else's precommitments. To be quasi-formal, the vows made back then are only morally binding on the fraction of your current self which are left unchanged from your old self.Or something like that.
Derek Parfit, on identity, talks about psychological connectedness (examples: recalling memories, continuing to hold a belief or desire, acting on earlier intentions), and continuity, which is the ancestral of connectedness. It sounds like you are saying that commitments should be binding based primarily on connectedness, not on continuity. But this has certain disadvantages. If I take the suggested attitude, I will be a less attractive partner to make deals and commitments with.
(I didn't downvote your comment BTW. But I bet my worries are similar to those of whoever did.)
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.