I'd do it in a heartbeat! Thats how much I would want to see her with another woman.
I'd do anything she asked. If she wanted to see me with another man, she already knows I've done it before. And, she knows I don't mind being watched. She also knows I'd be down to let a man have my ass while she sucked my cock. She doesn't even have to dangle the carrot of seeing her with another woman in front of me. I might like that. But, I'm more interested in fulfilling her fantasies -- especially if they include me with another man.