I have a friend whose wife, a non-diver, snorkeled (remained on the surface) above us when we did several dives during a trip to BVI. Excellent visibility meant she could see clearly what we were doing/seeing several fathoms below her. When we returned home, she immediately signed up for scuba lessons!
Maybe if you try that approach, your wife will end up becoming the dive buddy that keeps you from having to dive solo. (And just maybe she also will begin, eventually, to understand why diving solo can be such a sublime experience.)
rx7diver