Try to treat it like a new relationship. You both had pasts before you met each other. If you were to meet someone new, that person would have a past that included other women. If you both saw other people, he may be thinking the same thing you are. Give it time. If you are together now and committed to each other obsessing about a person he will never be with again is pointless and not worth your thoughts.

Thanks. Your comment was very helpful. I'm starting to try and force myself to think of other things. It's not just them sleeping together, I imagine her meeting his parents, hanging out with his family... ugh!!! What is wrong with me!!??

I understand what you are feeling. Our situations are very different, but my husband left me and our two children and is spending a lot of time now with a woman who he had an emotional affair with at his work. I understand that the thoughts just pop into your head. Like I will be working and all of a sudden I think of my husband letting my kids meet this other woman. Or him taking her to a movie or to dinner, him holding her hand or wrapping his arms around her from behind. You can't help it...the thoughts just happen. Let the thought happen then let it pass. Understand that all it is is a thought, nothing more. Take a deep breath and let the thought go. Smile and put faith into your relationship. Were you his first girlfriend? I am not sure how old you are, but if you are not a teenager, then he has probably introduced other women to his family before you even met him. You don't think about those women. Don't let this one woman who he chose to spend some time with while you were not together affect you so much. He chose you and is with you. Be confident in that fact and enjoy your relationship.

You may want to try thought stopping. You can Google it or get the book How to Fall out of Love with Someone. It is a behavioral approach to literally stopping unwanted thoughts from randomly popping in your head. It does take some time and practice, but you will notice that the thoughts of your love and the woman he was seeing while you weren't together will diminish if you make them. Hope this helps.

Thank goodness someone else has this problem (though I didn't see anyone else during our time apart). I shut his drunken one night stand out of my brain but from time to time there's a reminder and my thoughts go there. Even though she's not very attractive and it was nothing, I still have unwanted thoughts about it and start to wonder what it was like...picturing it is the worst.

My advice is to let the anxiety pass when these thoughts pop up. I used to have to take a xanax every time but now that things are settling with him, the thoughts pass quicker. I used to obsess for an hour, now it just takes a minute or two to get it out of my system.

I'd totally feel that way if mine brought someone around his family while we weren't together. I'm sure his family likes you much better anyway.