I've had a number of 3-somes with couples and most of the guys were smaller than me. Only one or two were equal to me or larger. Most of the girls went "wild" when they saw my cock, not to say it was the biggest one they've ever saw, just the girth alone seemed to be the kicker. One couple I was with had a guy who was over 10", but on the thin side in girth. Seeing a cock twice his girth made her go crazy once I put it in.
If you are okay with your girl fucking other guys, then go ahead and try it again.