Fears in relationships

So my last husband was a horrific experience! I was mentally abused and physically. Him and I divorced within a year of marrying. I didn't date for 3 years since him cause I was rebuilding my life and growing after that experience. I was doing great!! Then I met a wonderful man at work and got to know him and became his gf. We have been together almost a year and it's hard for me! I am always afraid I am not enough or worth it. Lately our shifts have been insane with double mandatory and working 6 days straight I haven't been in the right mind frame. I've been accusing him of being unfaithful and he's doing nothing!! I dunno if I'll ever be able to trust and not have any fears. He's a great man and the first man to ever treat me with respect. He never talks down to me and always encourages me and is still with me through a 3 month depression and all my crazy thoughts. I don't understand why I can't trust and jus relax! I don't wanna ruin my relationship but I feel like I am even tho he says he's still here. Why can't I love myself and belive I am worth it!? Why do I always think of the negative and make shit up in my head!? I'm so tired of not being my best me and not enjoying my great bf!! I jus needed to vent. I'm acting so dumb. I feel like a foolish lil girl!!