How was the intimacy before the surgery/cancer? There could be complicated reasons causing your wife's lack of intimacy. You may have already done this but try sharing your feelings with her and see if she will open up. Ask her what can you do to help her feel more comfortable. If you reach a sticking point then consider seeing a counselor/therapist., individually or together.
You should talk to your wife about seeing her doctor and have other hormones checked. She's nearing the age at which she could be entering peri-menopause or even menopause, which often causes women to have little/no sexual desire.
In addition, hypothyroidism could cause lack of desire, as well. I'm assuming that your wife is on some type of replacement thyroid hormones, but it's very possible the medication or dosage isn't what she needs. If you could let us know what her medication/dosage is that would be helpful.
It would even more helpful if you could post her most recent thyroid labs so we can see what her status is. Be sure to post reference ranges with any labs as ranges vary from lab to lab and have to come from her own report.
Many people who are hypo are also deficient in Vitamins B-12 and D, along with Ferritin. If she's had those tested, please post the results and ranges also.
Ok Finding answers. She was on Levrothoxine 150mg
Her labs as follows
T3 less than 1