Once Upon a time, (about five years ago) I dated this person (they/it), and at the time it was PolyAm - now that came to a crashing halt for reasons that included them not being comfortable expressing jealously, but we have stayed friends and occasionally swayed into more or less of a relationship.

After a break of about six months, we've realised that not being in each others lives is very difficult for both of us, but they are currently involved in a polycule that I'm not....totally on board with? it seems to be very new, but very intense, and my lover is aware of their position as a third priority, which just rubs me the wrong way.

They have also expresssed that if this relationship ended they wouldn't want to be polyam in their next relationship, which tells me they are uncomfortable at best.

Now I don't feel like I can demand they leave this situation, especially since they insist that it brings them joy, but the idea of sticking around and just letting them do this feels wrong. Dating them while they are involved in this feels like I'll end up comforting them and possibly extending what I am very sure will be a bad breakup. Trying to be "just friends" and maintain that this is none of my business feels negligent.

And the other side, what if this doesn't end? I can't just sit and watch this happen forever. I do truly love them, and I think I'd be breaking my own heart.

if anyone has any advice, Please let me know.