My hubby has actually was the one to buy 2 of the 5 tanks I have owned with him, b-day gifts. I also bring up ideas, mention how the fish/coral/expensive thing-a-majig will help make the tank "happy", let him absorb the info then hit with the cost. If he still says ok, a purchase is made. Buying personnel for the tank, he is right there with me, if he helps pick them out, he's more invested emotionally. Over the last 15 years, he has become a hobbiest-lite, he understands most of the biologics, temperaments of most common fish, etc. just don't ask him Latin names! Since the tanks are in the family room, going to the lfs is a family event. We usually have a short list of what we are thinking about before hand, see what the lfs has, ask a few questions to confirm research, buy, then out in unusually under an hour.
As the wife, always say hi to her before the tank. Fair is fair, expect to provide equal cost and time or whatever is "her" desire. Happy wife, happy life also works for husbands too!