Sex File: I still fantasise about my ex — how do I finally move on?

Sex file: Now I'm dating again, my ex keeps popping into my head in bed. How do I finally move on?
Sexual fantasies about former partners are a confusing, but extremely common, phenomenon. When they invade your thoughts during sex with someone else, it is difficult not to interpret them as an indication that sex might have been better with your ex — but it is not a fair comparison. You can't judge a person you have known for a week against a marriage that lasted maybe 10 years or more.