Not making general recommendations, just talking to this crowd . . .
All the tandem couples I ride with started like this: they both rode. Many of them rode on the same rides, but he had to moderate his pace to hers. One couple with Strava accounts, she'd climb at 145 HR, he'd climb at 115. So the females had some incentive to relinquish control in favor of equal effort for both, which also meant keeping up with the pack. Then they found they just loved it. It's kind of sexy, really. Dancing. That said, there are 2 couples where the female just couldn't give it up, maybe control issues, maybe trust issues. Doesn't work for everyone. I don't know of a male rider who didn't want to tandem with his SO if she already rode. I know female unattached riders who own tandems, too. Shopping for captains is apparently great fun.
When I suggested a tandem, my wife said, "But I can't keep up with you!" My reply, "On the back of my bike you can!" She went, "Oh."
Tandem couples do tend to be over 50. Maybe it takes a while for life to beat sense into us.
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