Why cant she just forget and not leave me over this past fling /?

why cant my wife who is leaving me over something that happened .5. years ago just forgive me and stay rather than go .when i was well fooling around with this now ex. married woman .she lives .5. states from us. my wife contacted this women.s .ex. husband. she has called him and knows he is.53. but dont look his age my wife is .20 aand planning on divorcing me she meet him while telling me she went to visit her mom. but meet him and talked to him . she had the nerve to tell me he was a very good man and had respect aat all times . that sounds like him . this i know from past meeting.s when i ws in that state . why cant she let him alone and forget my mistake. after all that was.5. years ago