So, you are saying you think maybe your boyfriend won't be satisfied with just seeing you once a week? and that maybe he'll then meet a monogamous person who will see him more than once a week, and leave you for that new person?
What would need to happen in order for you to see your boyfriend twice a week? How much compromising is your husband willing to do? and is he just reluctantly/resentfully going along with it, or is his heart in it?
Just trying to get a bit better understanding on the situation.
Love means never having to say, "Put down that meat cleaver!"