Advice for Lack of Communication/ Fear of Intimacy

I have been together with my boyfriend for about 6 years now. I haven’t had sex with him yet and I think it’s because I’m scared to get intimate and I don’t know why, but that’s one of the things besides communication that our relationship is lacking and I don’t know what to do. I don’t open up and to my family much about personal issues either and sometimes I feel like I don’t know what love truly is. But then I think this guy must be in my life for a reason because he keeps coming back even when I mess up. I guess I just really need help opening myself up to him more and taking this relationship to the next step which has been needed for a while. I feel like I need to retrain my brain so if anybody has any resources that would help me, if you could share them I’d greatly appreciate it.