askchapo

Talk to her about it. Being vulnerable is a prerequisite to a healthy relationship. Tell her that you're feeling this way (maybe leave the vulgar details out), that you recognize the feeling is unhealthy and unwarranted, and that you think talking about it will help. Make it clear that this is something that you are feeling as a result of your own insecurity, not something that is reflective of her behavior. If there's anything you want her to do differently then you can kindly request that she make a change, but if there's nothing she needs to do differently you should tell her that. What you probably want is some support and validation, and if you get it, you should respond in-kind by also reassuring her and making clear your feelings toward her.

Make it a positive conversation about your relationship and your feelings for one another. She might even have similar insecurities, or have something she's paranoid about that you can address together. This isn't a "real" problem, as in there's no material basis, and so it should be resolvable purely through good communication. If you're in treatment right now then you should lean on that. There's a lot that comes up emotionally in treatment, and getting past this is going to help you focus.

That's the place to start. She will likely appreciate the honesty and the vulnerability, especially if you're clear that you're not accusing her of anything. If this really is a non-issue, being open about it has a good chance of resolving it.