So me and my best friend of many years (21 and 22 NB, respetively), started "officially" dating a couple months ago. They are much more experienced than me romantically and sexually, as this is my first real relationship. I also have Bipolar 2 disorder (with mixed episodes and rapid cycling. yay me), which I am just beginning treatment for, if that gives you guys any extra insight.

We began the relationship as poly/open (they are dating someone else long-distance, and have a couple existing FWBs), and I don't have enough experience to know if I'm comfortable being poly, so I just accepted it. Our relationship was not going to work for them if we were monogamous, and I love them so much, that I am willing to do whatever it takes to make it work. We are normally very communicative and respectful of one another's feelings, and almost every part of our relationship is going incredibly well. Almost.

In theory I am fine with them sleeping with other people, and I don't feel jealous about their other long-distance partner, but there is this one FWB, that whenever they hook up, I spiral into depression and jealousy and insecurity that I don't know how to deal with.

I tried to set boundaries with them, where they tell me as little about the hook up as possible, out of sight out of mind, right? But there are little things that they do whenever they hook up with her, that I know whenever it is happening, and I can't think about anything else except for how she is probably so much better at sex than me, and that one day they're going to realize what a terrible person I am and leave me for her.

I tried finding my own FWBs or hookups to "even things out", and see how I feel about seeing other people, but all of them keep falling through in the talking stage. I'm trying to go to therapy, but nobody is calling me back, and I try to talk to friends, but they're all either monogamous or the kind of "natural" poly, where they don't understand what I'm going through. I just don't know what to do. I want this to work. More than anything in the world, I want this to work.

Idk what I need, maybe some advice or reassurance that these feelings don't make me a bad person.