My guess is it's the disease, not the medicine -- although the medicine can definitely affect the libido. I have had periods where I've had to really work on showing interest and commitment to my husband, not because I didn't love him -- I always have -- but because I felt disconnected from everything. And that's the disorder. But because my marriage is important to me, I did make an effort even through it was very hard. Maybe your wife is experiencing something similar.
What can be done to minimize it: try not to push it if you can. She will heal as her mood shifts and she will come around to herself again. She will come back to you completely. If she loves you enough to work at it now, she is not going anywhere. And she will appreciate it if you trust her enough to just let her be. Be honest with her, tell her you love her, want her to stay with you, that you're not going anywhere, and that she can trust you. And that's pretty much all you can do. Wait out the mood swings. Hope the medicine works sooner rather than later. Get her to the best psych you can.
I hope this is helpful,
Co-Moderator, Bipolar Forum