I’m self sabotaging

This guy I’m dating treats me very well and he’s the only one I’ve felt an intense connection with before. We’re both adults but he’s more experienced sexually and has had more relationships. I don’t have much sexual experience and only 1 relationship from when I was a kid. I was always a more reserved person so I never really dated around. Him on the other hand, I can’t get it out of my head that he’s slept with multiple people, has been in other relationships, and especially since that relationship ended a year ago which I feel flies by. A year ago he slept with more than one person and I can’t help but feel jealous. I feel our relationship or sex would be just another experience for him. I want to know him and experience him in a way that others haven’t, and sex is such an intimate thing that they got to experience before me. This feeling makes me want to distance myself from him, I get upset and insecure, and at times I want to end things because I’d rather not feel this way. I know this is something I want, I don’t want to ruin what we have but sometimes I feel I’m not ready to be in a relationship if I feel this way. What should I do? I know I need to work on my confidence and being present but these feelings can be intense sometimes and ruin my mood.