Sorry...but you've split with your wife...because of a stupid crush? And got angry that she couldn't remember a few acts of sex? Who remembers every time they have sex- I certainly don't! I'm sorry that this has happened to you but to be honest it just seems like an overreaction, or that you've been looking for a way to get out of your relationship and want to use any excuse. She is allowed to have thoughts and feelings, and is allowed to want things in your relationship, and she is allowed to look at other relationships and envy them a little.

To be honest, she probably didn't have a crush on the guy, but the relationship itself. Yes, you did so much for her etc etc but she's genuinely allowed to want more, even if its a little selfish. You told her all the things you did for her and made yourself look like the victim, all you were talking about was yourself, but you genuinely never talked about or considered HER. If its such a problem and you care about your relationship, then you'd find ways to fix those problems. There will always be issues in a relationship, but its about fixing them and growing from them. You didn't fix this one and you certainly didn't even think about why there may be a small issue, you just ran as fast as possible from it.