needy Boyfriend

So I've just recently got into a relationship with someone who is way above my ratings, and it's genuinely the most sweetest guy I know! However, considering I'm still virgin and he's 3 years older then me, when it comes to sex and shit I'm not exactly the one who knows what I'm doing! He knows all this but a 19 year old boy only really has one thing on there mind whilst in a relationship.... I'm prepared to loose it to him, but considering we've only been with each other for a week, I'm still not sure that he's the one.... I think the main thing that is holding me back is the fact that he's slept with a lot of other girls in the past, whereas I haven't yet been in a serious relationship?! What should I do?! Any advice would be lovely💗