Hi, my 2 cents worth. I'm going on my 3rd year as a sailor. I always wanted a sail boat and someone gave me one 3 years ago. It is a O'day 22 1977 vintage. Now, I want (badly) a larger boat but, I have an inner argument and a few obdervations to share.
Like you, my signifigant other was not very interested in sailing but I really thought she would love if I could get her out there. So, the boat was free but needed everything, Sails, an outboard (which I bought brand new for piece of mind) rigging, you name it. Anyway, after about $5,000 I have a really sweet little boat that I get tons of compliments on and have gained a huge intimate connection to given I did all the labor myself. The beauty of the small boat was that I could actually afford a slip instead of a mooring. This is definately the most important point in regard the GF.
It is so convienient to be able to go down to the marina walk right out to our boat and climb abord. It makes those last minute, forgotten things in the car so much easier to retrieve. Not so much for me, because I'm a hardcore at whatever I put my mind too lol, but for her and anyone else we bring along.
The 22' boat is very easy to maneuver around the other boats and is great practice for the larger one I dream of. I even have a trailer for this boat and simply have the marina pick it off the trailer in spring and launch and pull it and place it back on the trailer in the fall and take it home, saving on winter storage. From what I hear, it is also better to practice on smaller boats as they require more attention and react to the elements more giving the boat feel of your actions as skipper. I have only ever sailed a big boat once during an afternoon charter so, I don't really know how true that is.
Now, then there is all the costs of a larger boat as every expense is per foot. Bottom painting, slip or mooring fees, off season storage...blah blah blah..
We really have a great time on our boat, the GF loves it and has no dream of larger boats so, it is a very tough justification of getting a bigger boat, even though I scour craigs list and ebay constantly searching for the upgrade!
I hope my ramblings aren't too off topic or too, well, rambling and give at least something to think about.