Hi there. There are a number of possibilities for your wife's apparent disinterest in sexual activity. Here are just a few:
(1) She may be over worked and stressed and too tired to be bothered with sex. See what you can do to relieve these stresses if they exist.
(2) She may be on a medication that is dubbing down her libido. Antidepressants and the birth control pill are famous for this but any medication or drug, prescriber or illicit, can cause this.
(3) She may have Poly-cystic Ovarian Disease
. In any case she needs hormonal
assay including testosterone
I hope this helps you a little and good luck.