How many would consider using a tether when diving with a loved one?

[Akimbo]

That's a very odd way of seeing it I'd say. My recommendation would simply be:
- get her to do some proper training
- get proper training as well
- have fun

Two marginally competent people diving together is a greater liability than solo. The blind leading the blind so to speak. A very competent person who's primary concern is the safety of their buddy is a solo diver with a job to do.

 

[Hatul]

Hand holding may be nice in a calm situation for bonding purposes, but in heavy surge I need my hands free to protect myself or hold on to rocks. An anecdote comes to mind from a few years ago. A 20 something female marine was taking a wreck diving course on the Yukon. She descended with a buddy holding hands in heavy surge, and was believed to have been knocked unconscious by hitting her head on the wreck, and she subsequently drowned. Maybe the holding hands was related maybe not, but you do need your hands free to protect yourself.

As far as the tether, I would avoid coil as it tends to snag things easily, rather try a bungee (thick enough) with snap bolts at each end.

 

[phoenix31tt]

I hold my wife's hand sometimes during diving... when we're chilling, not when we have to be doing any kinda of work. It's not for security or safety or to feel comfortable. If we were in a rough situation (as we were in recently) such as strong surge or sudden current, i would not want to be holding her hand then. That takes us from 4 hands to be able to handle the situation to 2 hands between us. Doesn't make sense... again, repeated advice is more diving in conditions that you are comfortable with where you don't have to be a crutch for her.

Nothing guarantees your safety, not holding hands, not tether... but better practice, training and experience certainly increases the chances of being safe way more than hand holding or tethers do.