TBH, yes I have. When my T was married I sometimes wondered because we talked about sex quite a bit in my sessions. After she got divorced, when she told me she had a boyfriend, I wondered again. Last year when she went on an exotic vacation with him, I actually told her I couldn't stand thinking about her having sex with him. A lot is jealousy that her sex life was and is better than mine. I don't like to think about it so much, though. It's kind of like thinking about your parents doing it. I'd rather not go there.