u/Any-Consequence918

My boyfriend (M22) and I (nb22) have been together for almost a year, but were friends for about a year before we started dating. When I told him I had feelings for him for the first time, he expressed that he didnt feel the same way. I thought i got over it and we continued being friends, until a few months went by and I realized I still wanted him in some capacity more than friends. I told him I hadnt gotten over it, and he was more curious in finding out what i wanted from him. We started having sex, and were basically just best friends having sex for a while which was fun but I really craved the security of being in an exclusive relationship, while he was more hesitant to fully commit. After a few months we started dating, and it being my first serious relationship a lot of old wounds and challenges regarding insecurity and fear of abandonment have been coming up. I also have a bit of relationship ocd and often blow up small things in our relationship to mean he doesnt love me or want to be with me. We have been discussing having a threesome for a while, which scares me as much as it sounds like fun. But around a week ago, he discussed the possibility of opening up our relationship more casually. We discussed steps to take first, like exploring more kink/bdsm individually and then maybe going to casual meet ups or group play parties or going on a date together with someone else, all things that sound scary but also exciting to me. But what really makes me nervous is the thought of him exploring on his own, a lot of jealousy and insecurity comes up as it sort of taps into the core fear of mine that he will find someone better, more exciting, or that I am not enough for him. When we talk about it he expresses that his interest has nothing to do with a lack I have, but more that he is interested in exploring his gender and sexuality (we are both queer) while he is young. For me, my few sexual experiences before him were traumatizing in some way, where I often felt out of control and unlike myself, and I feel unsure about approaching casual sex on my own or if its something I would have fun with or desire without him. My boyfriend has expressed that if its not something I am interested in, we do not have to explore any of it, but I can't help the feeling that if I were to say that I would be cutting him off from experiences he really needs/wants. Again, I'm also not positive that I would be averse to him exploring on his own and me exploring on my own, but the thought scares me a lot right now and I'm unsure how to proceed, any advice?