Don't waste your time with an ex. She brought you a lot of pain so I would say good riddance. Stay far away, run, never look back, and if you need an ego boost then just let the new woman or women in your life boost your ego. Although I would say having sex with anyone for an ego boost, ex or not, is a bad idea. This is a question I would ask myself. It might not be a popular question but I would ask it. "If I accidentally got this woman pregnant, would I be able to deal with her being the mother of my kid? ". In spite of taking precautions it could happen. This might prevent you from getting involved with crazy women/psychos.