Is sexual relationship worse than emotional relationship when it comes to cheating??

So my husband of 14yrs had an emotional and sexual relationship with someone 10yrs younger than me. I am 33. He says she definately wasn't anything special in bed...it was just something "new". Is it bad that I'm more jealous and insecure about the sex than the emotional connection they had??? It all hurts...but I find myself obsessing over the sexual details ect. He told her he loved her, was gonna move in with her and had unprotected sex knowing she wanted to get pregnant. In the end he chose me....but I don't know if I should believe that's what he really wanted. I think there are other affairs he won't admit too. For instance he said he had a one night stand about 2 yrs ago.....that would be the first person other than me that he had sex with. I clearly remeber about 6 months after that he searched on the computer "can u have an allergic reaction to a condom" and said if he had an STD it was from me smh. Should I assume that was another affair or he was still worrying about the one night stand from 6mo prior????! Don't know what to do and hare bronging it up bc I don't want him thinking about those girls. He said he blocked it out of his mind....should I believe that?