If your feelings are valid then you should commit to a process with your partner where you can work on the relationship. If they are not valid then you should ask yourself why you are having these feelings. Is the lack of trust based on anything in particular. Sometimes these feelings can be an issue because there is something in his past or your past that is causing them. It is important to resolve the problem rather than these feelings which may just be the symptom. They may be how you manifest childhood trauma or his past with women or his past with you. Address why you feel this way with him. Gain an understanding of why you feel this way and what would help you to not feel this way. He may be able to make some changes that can help you with this issue. If he can't then a relationship counselor is needed so that you learn to work on this with specific techniques. That can be a matter of him respecting your feelings and acknowledging how you feel. I would start by talking to him. See if he is willing to see someone with you or focus on resolving your feelings about him.
Please press accept; this is the only way I am compensated