It will be very rare for you, or any one else, to find any lover who is still a virgin, and who has had no prior sexual experience. For example, these days it is not uncommon for men and women to settle down into a (hopefully) long-term relationship, such as marriage, in their late 20s or early 30s. By then, each is likely to have had several or even quite a few sexual partners previously. Rather than be concerned about previous experiences, embrace the fact that he is a sexual being, and likes passionate intimacy.
Just because he is somewhat experienced with women does not mean at all that he will stray from you. He likes and wants to be with you and no one else. His presumed healthy sexual past does not imply that he has a wandering eye or is promiscuous.