I am sorry to hear about what you are going through. In this situation, the best thing to do is to take time away from him. Breaking up with the love of your life will be hard but the future life you build together has to develop with trust. He should separately seek out counseling if there are any past unresolved issues that he may be going through.
I think you need space to clear your thoughts so you can find happiness again. Happiness doesn’t only stem from love that you get with a significant other but with friendships, familial relationships, and doing things you enjoy doing. The feelings of unease and distrust that you are feeling is a wound that you can’t heal if you keep picking at it (staying with him). You can even seek out counseling if you need someone to talk to and also we will always be here for you. Good luck and again I am sorry you have to go through this.