I'm proud to say that I've NEVER cheated on my husband (even when we were dating) and we've been together for almost 10 years (MARRIED for almost 3 of those 10 years).
Now at the BEGINNIG of our relationship, somehow my husband found it necessary to cheat. As a result, I have a step-daughter. But our relationship endured even that. It took quite some time for him to regain my trust, but according to HIS ACTIONS, MY OBSERVATIONS, and MY KEEN INTUITION (God gave women this special gift), I feel that he has been EXTREMELY good, honest, and faithful to me since then.
I don't know about anyone else, but I feel that often times we SAY that we won't stay with someone who cheats and then DO the opposite. Gaining insight from my OWN personal experience, I would not tell anyone to leave their significant other because he/she cheated----as you can see I didn't. Now I can't say that I would have done the same if my husband had cheated after we got married (things change drastically when you have a HUSBAND versus a BOYFRIEND).
I guess it's safe to say that EVERY situation and relationship is DIFFERENT and it would haveto be up to that person to decide whether they want to deal with it or not. I do believe that although MEN and WOMEN cheat, it IS possible for them to be remorseful and not do it over and over. It's really up to the individual.