I have a male friend that I've been close to for over 30 years. Any and all of the relationships I've had through the years have been under the condition that he is a life-long friend and that if he and I wanted to be together, we would have been together long ago. So, there is no reason to be jealous or suspicious of our friendship. Some of the men I have been in a relationship with have understood that and some have not. It's no skin off my nose. He and I are still close friends and he is living with a woman that seems to be good for him and I am thrilled.
Everyone carries some baggage from past relationships. If the person you are currently with cannot accept that, then my advice is to not tie yourself legally to that person.