My wife has visited enough petshops with me to know that alot of the corals & fish are expensive. She doesn't really ask anymore unless there's a fish she likes & wants me to add. Unfortunately, her choices are usually incompatible with my setups (porcupine puffer, jellyfish) or hard to keep alive for long periods of time (copperband butterfly).
Still, it's better to have her sorta interested than totally disinterested. BTW, it was her idea to get into sw tanks in the first place (I'd kept a couple of fowlrs in the 80s) after we got married.
She also knows I don't buy stuff unless its worth it (although our definition of "worth it" are different)
Anthony