IMAGINE spending every second of every day imagining your girlfriend or boyfriend having sex with someone else in a twisted fantasy you can't get out of. From the man who couldn't get over his virgin girlfriend having once kissed another man to the woman obsessed with her boyfriend's ex - victims of the disorder find themselves feeling excessively jealous, angry and upset about people their partner once dated or previously slept with. While experts say it normally affects men, experts older women are also prone to developing the condition as they struggle to let go of their youth and compare themselves to their partner's past younger lovers. Many sufferers compare their behaviour to that of an alcoholic or drug addict - depending on constant reassurance and for their partner to answer questions about their past - specifically, in many cases, the intimate details of their sex life.