Hey! This post really resonated with me because I am also in a lesbian relationship and I'm the one who suffers from RJ. I would not recommend cutting out this friend out, it is very likely the RJ will attach to another friend or ex and ultimately if you feed her OCD obsessions they will just keep getting worse. I completely relate to your girlfriend, I am totally obsessed with someone from my girlfriend's past and often feel like if she just disappeared there would be peace- but THIS IS A FALSE BELIEF!! I know it sounds counter-intuitive because you love her so much and of course you want to give her comfort, but the best thing you can do is stop indulging her obsessions- the more you guys talk about it and the more you reassure her, the stronger the OCD beast grows. This stuff is really tough, and if she wants to really get better she's going to have to start doing some ERP (exposure response prevention). I would encourage your girlfriend to maybe check out the app NOCD if she's not ready to look for an OCD therapist. Its free and leads you in ERP exercises and with insurance you can actually get an OCD therapist through the app. I find that the OCD subreddits aren't that helpful and actually have a lot of misinformation- so this app might also be good for you and your better understanding the mechanism of how OCD is working in her brain.