I don't think I'd ever be okay with an MMF threesome. Is there a particular guy she wants to bring in? or she just keeps suggesting that she wants it MMF. I would totally be down for FFM, I think the girl would enjoy it too, though, I'd rather just do it with her lol. At least with 2 females she could do things with the female, and it would seem alright. But two guys... what are you gonna do with the guy... other than glare with jealousy.

If I was put in this situation, I would probably just leave. I mean she already wants to bang another dude anyways..