My primary dive-buddy's wife hangs out on the boat, while we go diving. She's not even slightly interested in diving, unless it's something like a tropical location. I don't think she's "unsafe" in the water, nor does he baby-sit her, nor would she be "dependent." However, I think it would be natural for him to pay much closer attention to her safety during a dive, than he pays attention to me.
(...which wouldn't take much, since he's often gone before I've hit the water, and we usually dive solo)
When you start to get a little obsessive about a hobby yourself, it's usually a bad idea to drag along someone who is only casually interested, as it will usually just push them away from the activity. It's like a kid who enjoys playing music and is good at it, and then his parents force him to practice every day until he hates it and eventually quits entirely.