My wife is highly aroused by male/male sexual play. She usually can't keep from joining in.
We have received a number of responses from the female member of couples who want to see male on male sexual play, sometimes for the first time. It can be quite arousing. Even when they want just to watch, they often end up getting so aroused they join right in.
It's much more fun to have my wife with me when there is man play. It really broadens the sexual horizons.