I've seen this, and it baffles me. I know two couples who frequently dive together. In one, the man fusses over the woman, helps her with every little thing, and in the dive, she goes where she wants and he follows and watches over her. I think as a result, she has never really developed completely as a diver.
In the other couple, the man is often very critical of his wife, and you often hear their voices at their car, with his raised and sounding irritated. The wife is a good diver, but she doesn't believe it; her confidence has never blossomed, and I suspect I know why.
I think the dependency issues one sees in diving are often just reflections of the dynamics of the relationship above water.
When I found Scubaboard as a new diver, I began reading a lot of posts, and I found a member who became a major role model for me. Chickdiver, a technical and cave instructor, and former WKPP member -- I saw her as an amazing example of what a woman (and a small one to boot) could accomplish in diving. As a result, I challenged myself with learning to manage gear (and yes, I dive doubles, and yes, I carry them up boat ladders and cenote ladders and to and from the fill station. It isn't easy, but I've gotten to where I can do it.) And I learned to navigate, and to lead dives, and to take new divers out diving. And eventually I learned to cave dive. I think, if you asked any of my buddies, you'd hear that they view me as an equal partner in diving, except for the occasional assist with getting double tanks in and out of cars, or up on tables.
If your spirit is independent and self-reliant, you will be that way in the water. If you're a passive and helpless kind of person, you will be that way on scuba, too.