can't stop

I have not found a forum specific to my problem, but since it has to do with my relationship, I thought I'd post here. I recenty replied to a post about a man whose wife constantly thinks he's cheating on her. I know how she feels. I have delusional disorder. I constantly think my boyfriend is cheating on me. I know he isn't, but when ever I am away from him, or if there is an attractive female in view, I loose it. I don't know why, but I can't stop these feelings. My therapist says it's delusional. Just like people that think they are being followed by the CIA or PI"S etc. I am about to loose my boyfiend b/c he can't deal with my accusations anymore. I don't blame him. I wouldn't put up with anyone treating me the way I treat him. I am doing everything I am supposed to, with regards to my therapy, (rational thinking, not letting my thoughts which lead to my emotions, which lead to my actions get out of control) but I just can't. The only thing I've found that almost helps is to leave the situation. Like right now. We were sitting outside with a bunch of friends when they started talking about last weekend when my boyfriend went to a bar with "the guys". (We broke up because of one of my "episodes" on Thursday last week). The only way I could deal with it was to leave the situation. I know nothing happened when we were apart, I know how much he loves me, I just git this feeling in the pit of my stomach and I loose it. If there's anyone else out there that has the same disorder I would really love to hear from you. I am very early into my therapy, and could use some tips, and some understanding. People think it's something you can just stop. You can't.

have you thought about why you think he would want to cheat on you? even if you're being delusional, there's probably a reason you're falling victim to that particular delusion. do you maybe think he's too good for you or something?

yes think why would he cheat on you!?
if you cant we'll try to help