Is the trade worth it?

I am straight and so is my wife but she is really into seeing gay sex. She fantasizes about me fucking dudes with her, i role play with her, but the farthest i go is letting her fuck my ass with a dildo. She has this gay friend at work who has always wanted to fuck me and my wife is suggesting that I give it go if she could watch or join. Wife's sister wants to fuck and my wife wants to make a trade.
I can fuck her sister if I also fuck her gay fiend and her. I will involve me taking it in my ass and he chooses where he puts his load and I get to cum inside of the sister.
If it were you would you do it?