Accusing underwear to be purchased by a girlfriend is getting into some real paranoia. There is something called delusional disorder jealousy type. It's an extreme jealousy type but it might be worth looking over the symptoms of it as it could get worse and worse and she feeds into it. Just based on what you described, it might be worth a read over: http://www.psychforums.com/delusiona...opic69682.html.