First time I fucked another woman with my ex-wife [MFF]

About 10 years ago my ex-wife and I were visiting some friends of mine in Portland. I used to live with a couple of them in a punk rock party house in Kenosha, WI. One of my friends, let’s call her Sam, used to date one of my roommates. She was one of those brash girls, always ready to swill whiskey and talk about sex. She had a great body too — tone, nice ass, big tits. After she broke up with my roommate and moved to Milwaukee, I used to crash at a place she shared with other friends. One night I was on the couch, next to her bedroom, and I heard her railing her new boyfriend. It was just total hardcore: she was begging him to fuck her harder, yelling at him to smack her ass, all at full volume. I didn’t know if she was putting on a show for me or what, but I jerked off half the night listening to them. I should’ve just gone in and joined them.