My boyfriend of 6/7 months and I broke up at the end of November for multiple reasons but one main reason was the fact the he was struggling with the idea of being committed to a long term relationship (I did not know this at the time but was revealed to me later). It was a rough break up and it resulted in me blocking him on everything in order to allow myself to move on. Around three weeks later, he writes me emails saying that he regrets everything that he has done. A lot of discussion and going around in circles later, I decide to give it one last shot (we had argued and broken up very very briefly and then quickly reversed it once before). Since we got back together, things have been good, however, simultaneously, my self esteem and body image issues have been worsening. Recently, he told me that he had met a girl few times while we weren't together and they ended up having sex together.
The inevitable hurt that I feel (even though he didn't *technically* do anything wrong since we weren't together) and my extreme anxiety and insecurity all combined, keep making me think that he only returned to me because I am a safe easy option to fill his loneliness. I feel like a plan B because the other plan didn't go so well, and it's all really affecting my self esteem further obviously. I know he loves me and cares for me but I can't help this feeling. I'm too scared to bring it up to him because I feel like I have always been that person raising concerns in our relationship and having bouts of insecurity, and I don't want him to think I am restarting it all again. Please could someone tell me if I am overthinking and being silly or whatever?