I would definitely recommend talking to someone. I will tell you this - my XW fully apologized for an affair, and I had a very difficult time letting it go. Mostly because although she kept her pants on, she never really changed her overall behavior.
It'll be agony if you're stuck in between like I was for 18 months; so take it from someone who's been there, either LET IT GO and forgive even if you need professional help to do so, or you move on if you can't. But don't stay somewhere in between.
