Same here on the dumping part.

I think (or I'd like to believe) that we learn at least something from each failed relationship.
I've often regretted ever marrying my ex-wife in the first place.
Truth be known, I often still feel that way, even 10 years after my divorce.

But logically, I know that relationship happened for a reason.
I suppose the rub here is that sometimes that "reason" isn't immediately made crystal clear to us.
Perhaps it sometimes takes the next relationship to give us some clarity on the previous one.