traingang

assist-only bikes might be for you. they don't have a throttle they just help at a certain speed or torque to make the hills easier

For what it's worth, it's still great exercise. You burn 70% of the calories you would on a normal bike, but now travel is pain and stress-free so you go more places more often. While riding your heartrate stays in the healthy exertion range without spiking into uncomfortable territory, so you don't have to stop to catch your breath. Biking 20km to a park to check on a patch of wildflowers is now a snap decision instead of something that I'd otherwise plan around. If I turn down the pedal assist then I'm exerting the same effort as a normal bike if not more because mine weighs 40kg. I haven't lost any leg definition and get so much extra exercise from commuting that the rest of my body benefits.

It'd be worth renting a couple for a week from a local bike shop. Your partner would probably change their mind fast if they saw that every trip can now be exercise that feels pleasant instead of punishing. For me at least a regular bike feels like jogging while the ebike is like hiking.