things were really going well, or so i thought. we had been making some real progress. but now i found out that she is still talking to her AP, even offering to help him with his job resume. the problem is that, she doesnt know that i know, i found out through "other means" ie, she never changed her passwords after we split. what the heck do i do? if i approach her on what i know, then she will know that i have been spying. if i dont tell her, then........uugghh......this is soo frustrating.
When someone has betrayed another in a marriage/relationship, it is unreasonable to expect that the betrayed partner be able to just start trusting them again. I don't get bothered when I hear that a betrayed partner "checked" whether or not something was going on. SHE IS STILL LYING TO YOU. THAT should be the focus, not that you had to sneak around to find out the truth.
Be less concerned about her reactions and focus on how you can establish boundaries in your relationship. You are not safe with her.