StarGazer, thanks for your reply. You are right that perhaps I had the right to have sex with her, seeing as how he agreed. The problem was I knew he would be jealous considering his reaction to her compliments, and I did it out of opportunism. I did not lead the girl to believe it was more than just sex. She had told me her boyfriend gave her the green light to have sex with other girls as long as it didn't include a goodbye kiss because that was too intimate. I complied.
Quath, those are all very good questions. I don't see myself pushing away the other partner, but I have never tried a poly relationship so I'm not sure how I would react. Things did change when I slept with the other girl, I felt less close to him, but I think only because I knew that our monogamy was preventing me from spending time with her...because she genuinely did like me and I didn't want to have the temptation.
alphafour, thank you for the kind words. I am an empath, in fact, that is very observant of you. I only know perhaps two others like me, so it is likewise nice to hear from you. I do agree that NSA sex is NSA sex, but when you agree to be in a strictly mono relationship, polyamorous relationships are out of the question...so my inward feelings might not reflect what is occuring in my life. However, it's possible I'm just a swinger.