That's good news . . .
Youe wife's attitude gives you a big advantage IMO. She is placing a high value on your relationship and showing a high degree of loyalty to it . . . that's good, very good. The problems start when a partner has a higher level of loyalty to "mother" than they do to their partner. If the situation becomes "forced" . . . it's all over. Either your own discord about the truth . . . or the involvement of pesky Elders is enough to "force" the situation.
This way you have control of the timing of events. The first steps you can take could be enhancing your relationship with your wife even further. Become the best you can be as a Husband, Father, best friend and lover. This will enhance rather than de-value you in relation to "mother" and you will maintain her loyalty. The best way to do that is by appealing to the "authentic" rather than the "cult' personality. Keep away from matters JW for now . . . and engage with her and the family by doing normal family things together and having fun. You may have to go through the motions a bit on JW matters . . . but avoid points of difference. It merely invokes the cult personality, invokes fear and dilutes trust. That disadvantages you and is regressive.
Other posters here have successfully used the "family worship" arrangement to gently plant the cognitive dissonance that eventually results in others questioning matters for themselves . . . and that's the point you need to reach. It takes time and you often only get one shot. Reading Steve Hassan's books is essential for someone in your situation . . . they will help you get it right. leavingwt used the information to effectively release his brother and eventually parents and other family members from the cult. It takes a bit of time and patience.
All the best and do keep us posted.