stop being so paranoid

I dont say it in as many words, but, i accuse my girlfriend of cheating and after been cheated on so many times in the past i cannot get my head into gear to make me believe that not everyone is the same. If i cannot get help and/or talk to somebody i think that this will be it for me where relationships are conserned as i stew on the past whenever i feel something is not right which causes tension and anger between my girlfriend and i.I never tell her what to do she goes out when she wants and im not posessive over her, but i cannot keep going around all my life being paranoid. Where do i go ,who do i see? I dont now what to do. I do sometimes feel like i am not wanted, but who would want someone that is paranoid to this extent, well the answer to that is, “NOBODY”. So to put this simply i am a 22 year old male with no future of ever having a family or relationship that will last more than a year how because i cannotlearn to trust any partner fully.