Just a question - how sure are you about the affair? I mean, do you have messages that absolutely confirm it, or are you just making assumptions based on her staying out and being in contact with him?
Don't get me wrong - I suspect you are probably right. But it also might be remotely possible that she is just seeking to escape the pressure cooker that is being at home with you and your issues (not saying it's right, just saying if you have PTSD and anger issues it could be difficult).
Does she have any history of alcoholism in her family? Do you suspect she might have a drinking problem?
And, although snooping is generally frowned on (because some things you don't ant to know if you're going to repair the marriage), in this case, if you really think she's gaslighting you, perhaps it would be beneficial to get hard proof of an affair? Because if she's NOT having an affair, your suspicion is ruining the marriage. If she definitely IS, then at least you don't have to wonder any more and be subject to the gaslighting. Sometimes a PI, or even a keylogger program on the family computer, can answer the question for you.
