I (42f) have been seeing Apple (50m) for just nearly 2 years, every 2 weeks. Very recently I have started spending some time with his friend group and his partner (51nb). I also have a husband.

The agreement we have for social situations is to be platonic. We haven't told more than a very few people about the nature of our relationship, and Apples partner feels insecurity about me.

This weekend I'm invited to his partners birthday party. There are a lot of open people going so I can only assume there will be some sexy stuff going on. Apples 2 other people he is seeing will also be there...they're both newer in his life than I am and they don't have the same agreements in terms of not being physical with Apple around his partner because the same insecurities don't exist (they are more friends with the partner and also don't see Apple as much).

Problem is, I have insecurities about both of these women and I'm worried I'll feel just sidelined throughout while he can be open with and about them but not me.

I don't want to ask him not to be with them. I kind of want to share that insecurity with him but I don't even know if that's fair. He didn't even mention to me that they'd be there I just see them on the invite. I'm anxious about it which is blocking my logical thought.

Advice?