Perhaps a silly question but....Are you absolutely sure she likes men at all?
edit: To elaborate on what I just asked...You've been together for nearly 10 years and if she came to the realization that she likes women sometime during that time think how difficult it would be for her to admit that to you. It's one of the reasons why I've never ever wanted to get serious with any of my girlfriends through highschool and the early couple of college years; no one knows jack shit what they want.
If this hormonal therapy doesn't work, check the classifieds or something and look for a woman willing to have a threesome with you guys. Or even a guy. Try both and see her reactions.
edit: To elaborate on what I just asked...You've been together for nearly 10 years and if she came to the realization that she likes women sometime during that time think how difficult it would be for her to admit that to you. It's one of the reasons why I've never ever wanted to get serious with any of my girlfriends through highschool and the early couple of college years; no one knows jack shit what they want.
If this hormonal therapy doesn't work, check the classifieds or something and look for a woman willing to have a threesome with you guys. Or even a guy. Try both and see her reactions.