Forever tainted

I wasn't dating this person at the time but we were exclusive until I found out he was cheating behind my back all of the time (like all of the time multiple people). I shouldn't care anymore it happened so long ago and now I have the most perfect boyfriend in the world but I can't help but feel paranoid. Like I know not everyone is a liar who cheats but now I feel like it's something with me. Maybe I do something that makes boys cheat:/ idk but that boy fucked me up for future relationships. I want to love my boyfriend fully with 100% trust but id be lying if I said I wouldn't be tempted to look through his phone...because I am (all of the time). Is there something wrong with me?:( maybe just low self esteem from the past but I also think my bf can do better than me which also makes me worry.......any advice?