Talk her into having a girl instead... or as well!

"I don't know about a guy, it'd be too weird. I dont think i could do that gay stuff with him..."
"Oh, you wouldn't have to!! You could both just stuff me like a beanbag!" Jen was secretly dissapointed; the idea of her husband sharing her pussy with another guy at the same time was making her pussy drool. Mark thought about it.
"Well, does the idea of having a threesome with another girl turn you off?" he was definitely aroused by the thought of Kara.
Jen thought for a bit. He's probably thinking about screwing Kara. I wouldn't be able to do it with her. Thinking about it, she could probably get off on watching him screw a lithe young girl...
"Maybe, some girls..."
Mark picked up...
"... but never someone I knew. Maybe some lithe girl, young, graceful..." she drifted off into imagination.
Mark was stoked. If she was serious, he would be in schoolgirl heaven!
"Maybe," Jen said suddenly, a wild look in her eyes, "We have BOTH! That would be an orgy!"