Fireman, it sounds like she is sending you a message and you need to pay attention. If you ignore it, that could push her in that direction without your approval/knowledge. You need to face the issue together. Discuss it and maybe do some internet research together. Pixies is a good start but you might try a site called swinglifestyle.com. You can do a search on your zip code without joining the site and that will give you an idea of how many other couples are into that sort of thing in your area. I think you will both be surprised at how many there are.
Personally I think you are a very lucky guy that your wife is thinking along those lines (I wish mine would). It could work out well for you two so long as you are doing this together with mutual love and respect and a desire to satisfy each other's desires and curiosities.
Good luck and please let us know how it's going.