am I wrong for feeling this way?

Hi everyone, I need some advice, so me and my boyfriend recently started dating but we got to know eachother for a while now. My boyfriend confessed to me a while ago that one of his tinder past matches sent him a picture of a nude of her when he posted a picture of us together, he didn’t tell me until days later that this happened and he blocked her. Before we started dating he did say that he would get a lot of nudes from females on Snapchat. Well this really broke my trust because I feel like that’s something you should let your partner know. He sent me a sexy photo today and that thought lingered through my mind like “ what ifs”.. I forgave him but I still feel a sick feeling in my stomach whenever he sends something cause then I’m reminded of what he did. I let him know that I’m still feeling some type of way about it and he got all cold on me. I’m usually good at letting things go but in my past I dated someone for over 6 years and when we broke up I found out he was cheating throughout the relationship and I used to be so secure now I’m not. Any advice or anything I can do to help me get rid of these bad thoughts I tend to overthink a lot :( .