For me, once WBF left me to freely engage in the relationship that he started while still with me, I actually became the EA/PA partner. I think...I'm so confused if it counts as such or not, since I was the primary partner to begin with.
I had been pregnant when he cheated, and I lost the baby. It was a long drawn out miscarriage, and I had to have a D&C procedure and was on a heavily cocktail of antibiotics for a short while afterward.
After his vacation out of state (when the affair occurred), she came to visit him for a few days in our state. We were broken up at this point. I slept with him the night before she arrived, while I was being treated with antibiotics. Bad, I know, but I did - I was drunk and sad. I still sometimes think it's funny she got to sleep right in the same spot that I did 24 hours previously, and I know he didn't even change the sheets. They didn't have sex, because he got a mild...uh...infection from having sex with me (all the antibiotics I was on wiped out the healthy bacteria in his urinary tract), so I love that I ruined that experience for them. They did have oral. Only for her though, because he was hurting. Ugh.
A few weeks after that (I had gone NC with him), he was so remorseful that after spending time with her on the phone (they had a LD relationship) he would call me sobbing and drunk, saying how he made a mistake and just wanted to be with me, spend his life with me, and loved only me.
I didn't let that go on very long, I just recommended to him to get professional help for 6 weeks, and then he could approach me about it again in the therapist's office. I really felt like he was so uncertain of what he wanted, and I didn't want to hear it again unless he was in full committal to our relationship.
I still can't help feeling like maybe I was the OW to the OW...which is lame.