In my situation, H. and o.w. met 9 mo. ago. He has broken it off with her 3 times during the past 4 months, but each time the break up lasted only briefly. Reasons? First time, it was because I discovered it. Second time, H. had doubts and was, I think, trying to do the right thing and stop it. Third time, because H. and o.w. had serious trust issues (gee, really?) and he said that no matter what she said, he would not trust her. Also told me they argued all the time. They have since talked this out and are “serious”. I’m still DB’ing.
Most of us really marry only once. First love endures, even unto our dying day. And we never really divorce.