I had this issue with an ex. I never expected it. If he is saying he is single on a dating website looking for fun, don't be surprised if he has done this on multiple social networking sites. It's a huge issue and destroys trust instantly. I confronted my ex, not by screaming or making accusations, but by simply bringing up that fact that he has this site. He told me nothing was going on and yada yada yada. Trust was never fully rebuilt. I couldn't get over it easily and later found out there were similar instances with him. Now, your relationship is not mine, but I 'm just letting you know of possible similarities. You'll have to both come up with a solution to put your mind at ease without him feeling that his privacy is invaded. You two will need to communicate a lot on this issue. Make sure you pay close attention to his reactions and what he is willing to do to remedy the situation. Don't be demanding or unreasonable though. Trust is a two way street. Make sure he is earning your trust. Don't think YOU'RE the one with the problem and should just trust him 100% after this. You can contact me if you need someone to talk to about this situation, if you wish. I hope you figure out what the best course of action is.