Interesting thread.
My own partner enjoys photography, but draws the line at anything where she has to deal with aperture and shutter speed choices. She did the whole manual slr and darkroom thing with an OM1 a long time before I got into photography, and I think it took the fun out of it for her.
These days she takes most pics with her iphone and a little digital point and shoot, both of which are used for a little video too. She has a great eye for detail, and also loves to crop, and to be honest I admire her uncomplicated appreciation for photography.
Having a partner who is into photography, does not change my preference for shooting alone however, although we do both find ourselves with cameras together when on holiday.