I want to see my husband fuck another girl...

I have always had this fantasy. A big phat ass. Someone riding my husband. It’s what I masturbate to, and I would love to do it as a threesome. I have a petite body and my ass is pretty normal size, but he loves big butts and always has.

This is the problem. I get jealous easily and I feel like it’ll ruin our marriage. Anyone done this or want to?