Not once as an adult. My wife’s lack of sexual drive has greatly driven my curiosity to have a cock in my mouth and have a man’s mouth sucking my cock.
My wife and I swapped once many years ago with another married couple. Loved it! I think the sight or her taking his cock in her married pussy and the sound of her errotic moans of pleasure was more of a turn on than it was when I was fucking his wife. I cum so hard every time time I fantasize about it.