I agree with one of the other posters, your wife's body was built for multiple partners. There is actually a lot of science behind it (Read Savage Love's column from last week).
You should awaken this subconscious desire in her by taking her to those clubs you have in your pictures, dancing with her and inviting other men to dance with the two of you. Having a couple pairs of hands on her hips and running your fingers up her spine will make her hot, I promise you. Then kiss her really hard. You know, that kind of kiss that takes her breath away (cliche, I'm sorry), and invite the other man dancing with you to kiss her too.
Then you run your hand over one of her big breasts and have the other guy do the other. Trust me, you'll wake her up big time.
Then you can just enjoy watching her turn into what we call a huge slut, but biologically, her natural function.