How??-sorry it's so long

Before I talk about what's going on, I'm going to give y'all a little backstory. I was sexually assaulted and abused (mental and verbal) 2 years ago by my now ex. Most everything was outside of my clothes, minus the time I gave in and let him grab my boobs under my clothes just to get him to stop asking. All the other stuff was he'd try to put his hand down my pants, he made me look at/touch his dick while he still had underwear/pants on, grabbed my butt God only knows how many times. Now to my current situation. I am currently with an amazing man, we've been together almost 8 months. This man wouldnt hurt a soul, unless you hurt his family, friends, or me. We've both talked about it and would like to go a little further, basically, he wants to finger me. I want him to finger me. But what happened before him, what almost happened...gets in the way every time. I just tell him that I'm not ready or that I want to wait a little longer and he's totally okay with that. We were cuddling at his house a few nights ago when he mentioned it. He said that he just wanted me to feel comfortable bc I thought he was mad I wouldn't let him. When he said that, I held him a little closer. He has no idea any of this happened. And I'm scared to death to tell him. It took me having a complete meltdown and falling apart right before church (of all times) for me to tell my own mom. Before this all happened, I never understood why it took people so long to talk about I know why. Am I over the breakup? Of course. Am i over what he did to me? Yes but things like this leave scars on who a person is and it makes you feel ruined. How am I supposed to go further with him with this running through my mind? How am I supposed to tell him without absolutely losing it? It doesn't help that he is the guy I was supposed to be with when I met the other guy, but that guy got in the way and messed it all up. I am 20 and my bf is almost 21. Please no rude comments. Thank y'all in advance❤