It's really not that much more work that keeping freshwater. Same water change schedule and other maintenace. The only real differences between a fish only saltwater tank and freshwater tank are 1) the margin for error 2) you need salt and a hydrometer. FOWLR (Fish Only With Live Rock) is even more stable as you have the live rock doing some of the maintenance for you with the nitrate eating bacteria inside the rock. Reefs are more difficult, but low end ones with soft corals, mushrooms, etc. aren't that significantly different than maintaining freshwater. It's really not that much different. A little more equipment dependent though.
saltwater keeping is not hard work, despite what people say. All it takes is patience and research and you should do well..Why dont you come on over to the marine section and let us know what you would like?...
Freshwater tanks are still cool... you don't have to have a nemo to have a good tank, I'd try a freshwater first, just 'cos if she's not likely to keep up with the (albeit only slightly more) maintenance it may end up being you who does all the work (but some people enjoy that...)