Relationship help!!!

My last three relationship I've been in have been with guys that are very controlling and/or abusive in one way or another. With each of these guys I have talked about marriage and planned somewhat of a life together but then out of no where things completely changed and they would cheat or become even more abusive. I am wit someone that is in many ways Is different from the guys I've been with before and I truly am in love with him. He helps make me better everyday but I still am worried that things with us are going to change and am quite worried he is going to leave me. I don't feel like I'm good enough to be with him a lot of the time bc he treats me so well. And I know it's from all the mental abuse I've endured over the years but how can I get over it and be able to fully trust him and put full effort into our relationship? I feel like I'm really holding back lately bc I'm very worried about gettin hurt and left again.