It's hard to give advice without knowing what your wife is like or what your sex life was previously, but as an older woman I can tell you what works generally with most women. You could remind her that the bible says a wife is obligated to "render her due", and that applies even if you are not a believer, but you don't want her to have sex because she has to, that would not work for either of you. I was stuck in a marriage like that, by the end I couldn't stand to have him touch me.
The big difference between men and women when it comes to desire is that women generally need to feel affection with someone before they will desire them sexually. If she isn't feeling romantic towards you, it will take work to get her feeling that way again. The thing men sometimes forget is that you need to be romantic all the time, not just when you want sex. Do you hold her hands? Do you give her compliments? Offer to help with the dishes once in a while, just because. Do you go out for dinner with just the two of you? My husband and I have "date night" every week. If money is an issue, date night could be Netflix and a bottle of wine. The point is that it is just the two of you and no cell phones or computers. You could also go for walks with her, that will give you time to talk and start feeling connected.
At first you need to do these things with no attempt to have sex. Otherwise she will just feel manipulated. If you do these things and she responds with affection towards you, then you can move towards more intimacy. At first just kissing. If she responds to that, you go a little further. Let her set the pace, do not move to the next step until she is ready. Once you get to the point of intimacy, don't blow it! Patience is a virtue. Do not attempt sex unless she is aroused, foreplay is very important. If you do not know what turns her on, then ask. If you have been communicating well otherwise, then you both should be able to communicate about this. If she doesn't know what turns her on, then you have a problem. The best way for women to learn what turns them on is self stimulation, but of course JWs are usually afraid to do that. You can still figure it out if you are both willing, but it will take some work. In general, women rarely climax with only vaginal intercourse, they need other kinds of stimulation. If you want her to have a good time, then you will have to learn what works for her.
If she doesn't respond to any of this, then your problems run deeper. Possibly she didn't ever enjoy sex and was just doing it to please you. If that is the case, you will have a much harder job. If you want to save the marriage you will need to see a marriage counselor. If she refuses, then you might have to consider divorce. In my experience many JW marriages were like this, for whatever reason. Sex is important and a marriage cannot be fulfilling without a healthy sex life, so it's worth investing the time to make it work.
