Thanks for bringing your question to JustAnswer.
When a woman goes through menopause, she often will begin to feel as if she's losing her sexuality as well. Your wife has a "double whammy" in that she's facing a hysterectomy as well. These are usually only done in cases of disease or pain. Under those circumstances, it would be very hard for a woman to feel sexy when her body is turning against her.
If there's some way you could remove the sexual pressure from your relationship for a few months, it will pay off for you in the end. To feel that she's letting her partner down, or to feel the pressure of his needs while her hormones are making the thought of sex itself distasteful, will make sex feel more like a chore or obligation rather than something to look forward to, for her. She is probably very frightened of the surgery, and affected by the thought of losing her female organs. Hard to feel sexy under those conditions, no matter how much you love and desire your husband.
If she had just been diagnosed with cancer or some other serious disease, you would find other ways to show your connection. That's what she needs now--to feel you still love and value her, even while she can't have sex. There will most likely be a 6 week restriction on sex after her surgery.
This is a time to work on keeping your connection strong, without involving sex until she is fully recuperated from the surgery. It would be a great gift to her (and your relationship) if you took care of your own needs yourself for the next two months, to relieve the pressure for sex. In the meanwhile, keep your physical connection with her strong by making a point of touching her in an affectionate (but not sexual) way as you walk by, offer to rub her back or feet when she's tired or scared, or buy her a session with a massage therapist to show her how much you care.
Don't underestimate the havoc that hormonal changes can create. This isn't personal, and it sounds like the loss of libido is hurting her, too. Once she is through the surgery, and fully healed, and her hormones have been successfully adjusted, she'll be back to her old self.
Think of it as her being in a medical crisis right now, because she really is. Facing a hysterectomy is very frightening, and can make a woman doubt herself. Being a stand-up guy through this crisis by removing the sexual tension in the home until she's completely healed will show her how much you really care, and will be your best insurance of a healthy sex life together when this is all over.