As much as I like the "space" offered by my wife not diving offers I'd love for her to take up diving I know she'd love it. We've talked about it on many occasions but her fear of water seems greater than the desire to learn to dive. Its such a shame as she gets more excited by my underwater videos than I do.
We are not rich so when it comes to planning possible holidays we are always at odds as to where to go. She can't swim and consequently does not want to go to the tropics. This sometimes results in us taking separate, overseas anyway, vacations. We used to snowboard together which was awesome, a shared interest and all that, but as she's gotten older she's no longer so keen.
So anyway, cool and congrats to you and your wife, well worth the additional expense. Added bonus I imagine it will be easier for you to buy new diving toys for yourself, or not I guess if she starts taking note of "actual" cost of gear. I'd be in trouble if my wife took up diving as I'm always white lying about how much that new piece if dive gear actually cost.