Have you talked to her about it? If it's really because she just isn't as crazy about the sport as you are, then the advice to let it be and be thankful for what interest she does have is valid.
If not, can you have an honest, introspective look at yourself and determine if it might be because you are pushing her too hard in terms of terrain, speed, length of day, desire to "improve"? If so, are you willing to have fun, for example, on the groomers, if that's her preferred terrain... without any hint of frustration?
I am the lunatic in my family. But am very lucky that my DH also likes to ski and we do ski together most of the time and I've learned to rein myself in.
We ski sometimes with a friend who is 20-30 years our junior and who is a very fast, aggressive skier. While the challenge is fun, it can be exhausting, and I can only imagine how it would feel if that was my spouse. That experience gave me perspective.
Imagine how you'd feel if every single ski day you are struggling to keep up, never feeling the joy of that "flow state" for the pressure to keep up or measure up.