I would definitely TRY skiing. From my experience, the learning curve is shorter.
Although, I do agree skiing has so much more stuff that it can get in the way of riding than a board. There are 4 edges on a ski instead of just two on the board. I'm a surfer too, so boarding seems more natural than surfing (but in surfing, your stronger foot is in the back of the board instead of the front).
If you are hesitant about trying skiing, think of it this way: skiers won't give you as hard of a time because you can say you tried skiing ... and if it is still not your thing, no big deal. If you end up still sticking with a board, hopefully your GF won't mind.
In addition, I know snowboarding is my winter sport of choice because the alternative (skiing) does not give me a rush as much as boarding.
