Husbands past

I just can't get over it. 
I was only with one person before I met my husband. My hubby however, was with about 50 women before I came along. We live in a small town so I see these girls all of the time. Every single day no matter where I go. And if I don't see the ones that I know of, I'm constantly looking at different females wondering if they were one of them. It's driving me crazy. 
He was in a long term relationship and got cheated on in a terrible awful situation. So after that he just slept with everyone in a desperate attempt to not be alone but also not let anyone too close. But there are people on his list that range from our buddy's-now-wife to a bunch of moms with kids that are older than me. 
It has always bothered me and I have always been told by other people that I'll just get over it. I tell myself all of the time that it's not logical to get this worked up over his past- but I still do. I didn't really know him before we started dating and we both fell for each other fast. Had I known about his extensive past I probably would have never even looked in his direction.
Now I'm 12 weeks pregnant and we are so excited. I just really want to find a way alto deal with my jealousy and frustration before the baby gets here. He really is the sweetest man to me, he treats me like his queen. I just don't know why I have to hold on to these bad feelings.