My partner and I connected with a guy a while back for a threesome. It went great, we all got along well, and eventually did a same room swap with him and his partner. Also great.

Here's the rub: My partner and I are open to playing individually or together. For this other couple, he's only allowed to see couples, she can do whatever she wants. They want my partner to come play with the female half solo while the guy (who totally gets off on this dynamic) is out of town, but it's off the table that I'd receive the same in reverse. To be clear, I'd have no problem with my partner joining them for a threesome--it's the inequity of access that bothers me.

Am I a jerk for not supporting this/feeling a hurt that I'm the only one who's "off limits" for solo play? Suggestions on how to communicate this to all parties involved/how to navigate this situation?

Edited to add: We've all hung out a bit now and I/we really like them as people. I'd like to preserve the friendship if possible, hence the ask for suggestions on how to navigate.