I have been through this twice with 2 sets of friends. I couple stayed together, 1 couple split. The reasons were of course complex, but at the core the issue seemed to be: a - the reasons why the other person strayed b - the willingness of the injured party to forgive c - a joint wish to stay together if possible d - children Where things broke down completely there were no kids and the straying party was bored in the relationship, the couple had moved apart as people and there had been an unsuccessfull attempt at IVF. Their reaction to the lack of success was very different with the injured party being quite sanguine about it and the one who strayed being bitterly disappointed. This then led to accusations of lack of support and a breakdown in trust and respect. A new partner was found who was newly single and new and shiny and so that was the end of the marriage. Where things were mended there were 2 kids - much loved and a lovely home. The problem was that the straying partner was spending most of their time away from home, was under huge work stress, had lost their father recently - this had brought up deeply buried issues from childhood (nothing sexual) and all of the precipitated a huge mid-life crisis. The straying was symptomatic of all of these problems. The inured party was of course angry, hurt and very bitter BUT could see what the issues were. Both parties fundamentally wanted the relationship to work and both were willing to put their family and their relationship before themselves as individuals. Much more time is now spent together as a family, there is much more talking and listening, there is a much higher awareness of just how much they rely on each other, mutual respect is now even stronger. I am not saying that things are perfect, no relationship is; but I uld put money on them being together for ever and ever amen.