This is a difficult one
My ExH left me for a French tart many years ago.
His ability to rewrite the last years of our marriage was rather amazing really! He had, he claimed, been unhappy for a long time - long before his affair had started (he was having an affair for 2 years before I found out). Now in that time we'd done all the usual things that married people do, holidays, fun weekends, time with friends etc etc.
I do believe though, that at least in his own mind, he really believed that what he was saying was 'true'. That being the case, I can see why the French Tart might have believed it too.
I think it is the case, that often the leaving partner has actually started to leave the relationship long before the left behind one is aware of their intentions. This does result in two very different perspectives of the last months/years.
I don't really have terribly strong feelings for the French Tart now - although I did at the time. They split up a couple of years later, as he moved onto the new conquest!
I don't think I would ever trust a man who has had an affair! Ever! I would bet that those who are with men who played a part in the breakup of their previous relationship will find that in time, they too are on the receiving end!
Highly unpleasant little toads that they are!!!!