OCD surrounding my (lesbian) relationship

So me and my girlfriend have been dating for 6 months and have a super strong connection (lesbians iykyk). We met the first week of our freshman year of college and now it’s summer before sophomore year. I am absolutely in love with it her and she is my favorite person in the world. I feel so safe around her and feel like I can tell her anything. She also has OCD, but a different flavor than mine. My OCD presents as being scared of abandonment and that people are lying to me, and magical thinking surrounding that. Hers is related to some past traumas and is very much about her being a good person and making the right choices for her. We both want guarantees in life and can’t ever get them, and we work through it together. We know not to reassure each other and to approach a fear or worry with the attitude of “everything will be ok even if we don’t know the future”. This makes our relationship even stronger and I believe we grow closer because of it. It’s still hard though and life isn’t easy living with OCD. She is working at a summer camp almost all summer and I’ve been able to see her on the weekends which has been really nice. Working at camp is the best option for her because of her mental health and family situation, so even though I miss her a ton I know it’s the right choice for her. Her best friend since high school also works at the camp and will get there soon, but I just feel really jealous and worried about it. Mostly because my girlfriend and her best friend used to have feelings for each other. I know my girlfriend doesn’t feel the way she used to about her friend, but I’m scared she will. I’m scared she will realize she still loves her friend romantically and it will ruin everything. With her OCD, she isn’t really sure of feelings sometimes so I’m afraid she will have something in her that still likes her friend. For some reason I just can’t handle the idea of that. Maybe because I’m afraid of being abandoned or that I’m not loved as much as someone else. I hate that I feel this way and I don’t want to feel these jealous feelings. My girlfriend and I are very open and honest, so we talked about it and she understands and listens, but doesn’t reassure which is good but hard. She loves her friend so much and is so happy around her, but what if my girlfriend loves her more than me? We build our relationship off of trust and I know she would never do it but what if she cheats? They are so close and sleep in the same bed When they have sleepovers and stuff which makes me uncomfortable, but I guess I just have to be ok with it. When talking to my girlfriend about it she just says that she understands and that it would hard to feel the feelings, but doesn’t reassure necessarily. She tells me the truth that she doesn’t have feelings but other things that make me uncomfortable aren’t being reassured. That’s just how it goes but I’m still just uncomfortable. I’m about to not see my girlfriend for 3 weeks and she is going to be working with her friend and on the weekends they will be camping. Her friend’s mental health is pretty bad right now so they definitely want to have time to talk and be together, but I’m just afraid something will happen. What if emotions are high and something happens between the two of them? I don’t know how I’d get through it, because to me that’s betrayal. That’s cheating if anything romantic happens. I think I’m talked to my girlfriend about it before but it’s just not an easy thing to ask. Like saying “oh can you not sleep in the same bed as your best friend because that makes me uncomfortable?” It’s not a fair thing to ask necessarily. I guess lm just jealous because she is my favorite person and I don’t get to see her for a few weeks. Her best friend hasn’t seen her in months so I guess it’s fine but I feel like I sound so controlling. I would never really say a lot of this to her because it’s not fair to her but it’s hard dealing with feelings of jealousy and worry. I trust her so much but my brain has doubts and just wants a guarantee.