He knew something was wrong. I did not ask him to stay. I was still tasting the vomit in my mouth.
He left and called me on his way home home, a tempature check. He asked if everything was alright. I said it was and ended the call.
Should I tell him that I saw the call? If so how? When?
Right then, in my opinion. "No, it's not. I enjoy spending time together, and I'm glad that you say you want to work on this, but it's incredibly disrespectful when the woman with whom you had the affair calls my house. If she continues to call your phone, then I would ask that you leave it in your car when you come to our marital home. Thank you for respecting my boundaries."
VS2D, you hold most of the cards here. This is your chance to take it slow, as others have said, and to do it on YOUR terms, and in the way that feels authentic to you. If something bothers you, you need to speak up. Do you really want to walk on eggshells again?
I never got a chance to respond to your initial post, above. Personally, I'm a big proponent of the "I'm not sure how I think about that; I'm afraid it's no longer that easy" approach. The #1 "piecing" mistake that people make is accepting their wayward spouse back TOO EASILY, and without laying out what your dealbreakers are.