[nteracialcpl]

We had a very similar situation, except that, to demonstrate the difference between a good, respectful relationship, between consenting adults, and, what seems to be transpiring in your situation, when my g/f expressed that she wasn't yet comfortable with having intercourse with the other guy, he respected the boundaries.
We continued to be friends, and, though I didn't avail myself of the opportunity to have sex with his wife, any longer, the offer still was available.
The "girls" played, a few more times (before his untimely, unfortunate passing), and, never was there felt to be any undue pressure to do anything that anyone was uncomfortable with.
Now, to be honest, I can place myself in the other, older gentleman's shoes, in the sense that we've, also, run into couples that want to play w/her, but not, necessarily, w/me. She's attractive. I understand that, and, accept that that situation is, more or less, to be anticipated, if not, expected.
To this point, she has not wanted to play, w/o me, or, with another guy. If, and/or, when such occasion occurs, I'm hoping that I'm able to be mature enough to accept that, in this lifestyle, one is going to have awesome, excellent experiences, that'll never be duplicated in life, and, I've been allowed other women, as a result of our participation, so, if/when it's her turn, I'll be able to take it in stride.