[MF] Would you let your girlfriend peg you if in return she allowed you to bring another girl in bed.

I know it’s not a story, just something my girlfriend kinda joked about. Want some other opinions outlooks/ stories

Some background. I’m a 21 year old straight male, who has done very little but play (I think it’s meh). She is 18 we’ve been dating seriously for a year, I’ve watched her kiss a few girls(joined once), but never a threesome. She hates when I watch porn, and gets jealous very easily, but also said she’s into the idea of threesomes. What do y’all think? How should I bring it up? Would you do it?