Hi and so sorry you are having this problem. I think it is menopause or perimenopause. Your hormones change and your sex drive goes down or sometimes gone. Are you in menopause yet? Probably your hormones are off. The other thing is some drugs cause this to happen such as anti-depressants and other drugs. If you are in menopause you might be able to take estrogen replacement. That would help.
Agree with the previous poster. Menopause or peri menopause could be the culprit.