Fantasy and reality can be two very different things.
MMF double penetration.
Although..given the right couple, or an amazing energy level between me, a woman, and another guy, I might go there. Probably would, in fact.
I can count on half a hand the number of women that I would engage with sexually. Mostly it was a deep energy spark that was there for some reason, that drew us both in. If I bumped into someone like that again, and there was an attractive guy there who was also into it, then it would get a serious consideration.
I'm not going to entirely discount that situation would pop up, but stranger things have happened.