There comes a time when maybe you need to get past this. I know that sounds harsh, but you appear to having a loving & patient wife who deserves to be shown affection & yes, sex! is a part of this.
Lights out is a great way to avoid a visual encounter. If that is your concern.
Naked cuddling is also a great way to be close and allow your body to relax with hers and become aroused.
I doubt she will be judging you. You need to take a deep breath and allow her to love you, all of you.
What do you say?