New guy after sexual assault

*Trigger warning*

Seven months ago I was sexually assaulted by my best friend and for a few months after that I couldn't handle even the thought of being with a guy. (I'm in therapy so that's not what I'm here for) But a month ago things changed when I met this incredible guy, he knows what happened and has been so supportive and all around incredible but I've been having problems relaxing and orgasming during sex. He's so caring and always makes it clear he'll never make me do anything I don't want to do. So my question is does anyone have any experience or suggestions on what I can do? Thanks lovelies x