Am I the only one that thinks buying an E-bike in this situation is a terrible idea. The subliminal message of that would be horrendous on her morale.
A tandem is a great time for a married couple, but not a cheap options. Personally, is it that hard to just roll at her pace?
My quick suggestions are for you to ride a mtb with knobbly tyres, and make sure she has a light bike with thin tyres.
How about you carry a heavy rucksack with all her water and tools (and however much extra you want to carry, you don’t need to necessarily tell her exactly how much)
And another suggestion is for you to go out on a pre-ride for an hour or so where you do a lot of sprints and so knacker yourself out before you go on the couple ride.
Best of luck with finding something that works.
That’s a bit different than some random Fred telling his partner “here’s an e-bike so you can keep up with me because I can’t be bothered to ride at your pace”
E-Bikes have their place, being shoved at a loved one in this way doesn’t seem like a very good fit.
The end application might be the same, but how you get there is 2 completely different things.
Another question for the OP:
Who is this discrepancy a problem for? You or your partner? Is she complaining about not being able to keep up with you? Or are you ‘annoyed’ by having to noddle along with her?
It totally depends on the situation. Are we talking about riding together for an hour or two once a month just to smell the roses? Then you’re right, OP can choose to just slow down.
Are we talking about training together 5 days a week? Are we talking about going for long weekend rides in the mountains or on gravel? Totally different situations, and ones where an ebike is a great solution.
I’m not getting the vibe that his wife is a hard core racer but one who just likes going for a ride together. She probably already knows her partner needs to slow down for her. Just ask her if she wants an ebike. If yes, let her pick out the bike she wants. If not, slow down and enjoy time together. Why would someone be offended by that?
True! The whole tone of the post seems pretty patronizing. Maybe I’m more at the OP’s partner’s ability, riding at 100w is pretty easy, but no reason I can’t do that to hang out with my partner.
Let me reverse this for you, how would you feel about this convo from your hypothetical partner:
“I got you this aide to help you last longer in bed because your endurance has become a detriment to my enjoyment.”
Because nothing in the OP state’s their partner’s opinion on the matter?
Longer, more frequent, and more enjoyable sex where we both end up happier at the finish? Sign me up!
That’s a PED I’d be willing to take. 
It depends. If her zone 2 (high zone 2? low? mid?) is your zone 1, you might or might not be that far from each other. What is she riding? What are you riding? How long have you each been riding, how often do you ride together, and what are each of your goals?
My boyfriend and I ride together. When he is on his road bike and I draft, I’m high zone 2 and he’s mid-low zone 2. Not perfect, but not a waste of time. If he rides his gravel bike and I ride my road bike, we can both stick zone 2 side by side. On hard group rides, I inevitably get dropped by him and just about everyone else. So we talk goals for each and pick meet up spots. He’s been racing a few years and I’ve only been trying to be competitive for ~6 months. I have hopes I can keep up eventually, and him pacing/pushing/supporting me is wonderful. Not enough info in the OP to know if this is anything like your situation.
I’m with a couple people above - sounds like a good excuse to buy a MTB or Fat Bike Even.
EBike
I am a slowish but experienced cyclist, wife of faster cyclist, and completely agree with you.
At 50, the message I hear all the time is is Use it or lose it. In 40s women start losing muscle much faster than men (then falls off a cliff in 5Os), so if I were the fitter husband, I’d want to do whatever to encourage wife to stay active now so it’s easier to do things in together in future.
And having grown up with tandems as a kid (my mom can’t balance on a bike) they are not at all as fun as riding your own machine. Guys, seriously, try it sometime.
When we ride long or tour together, Hubby rides his steel touring-turned-gravel bike and carries most of the gear.
But on regular rides he’s just happy his wife is a roadie too (much to amazement of his riding buddies) and is content to pedal slow.
OP - Maybe could find harder group rides or races so when you ride with your wife you’re quite happy to ride easy?
Of course, an e-bike is only the “perfect solution” if it is what the partner wants. The OP is going about this in a good way - it’s the OP, not the partner, who has the issue and wants to change something. Maybe she would like to work on her fitness and not just chill on an e-bike?
You need to equalize w/kg and W/CdA
W/kg to even it out on the climbs is an easy fix, just add weight to your bike until your w/kg(including bike) are the same as your partner.
Reducing you W/CdA to even you out on the flat is going to be a lot harder. Fitting some spacers under you stem to make your position more upright will make the biggest difference, baggy clothing next.
I appreciate how hard it is to keep the power steady at easy Z1 and not drop a weaker rider on your wheel, what is only a few % of FTP increase at that pace for me could be and 10% of FTP increase for a weaker rider and that’s enough to blow them off my wheel.
I’m going to regret jumping back in here, but …
I fail to see how an e-bike is patronizing by default? At least without more information … which I’m not entitled to, nor do I really need.
Coaches are now using e-bikes regularly so they can ride with the pros they train. They have to do this to keep up. I think it’s an elegant solution.
All I read here is someone trying to find a way to integrate a loved one more fully into a hobby they both enjoy.
Whenever I ride with my wife on my road bike I actually get fatigued in the shoulders, neck and lower back much quicker because of the lack of torque I’m putting into the pedals. This is why riding my MTB when I’m with her is a great solution for us. I’m more comfortable, slower and we get to enjoy some bike time together. I even paced her to a neighborhood QOM one time, which was great fun for her (and me!). She’s never felt remotely patronized when I ride that bike …
(I just went and asked her to confirm. Her response: “are you on that message board again?” Lol)
I don’t know … are we being overly sensitive here? If the couple in question were of the same gender (maybe they are?) would this be viewed as similarly patronizing?
My wife kicks my butt at tennis … and I don’t have the motivation or drive to put in the work to be as good as she is, but we still like playing together. I never feel patronized when she feeds my forehand so we can keep a good volley going.
Let’s just help out someone who is trying to piece together scarce time with their partner, and let them figure out any, all or none of the implications it has on their relationship.
Right?
Because people are assuming that riding an ebike is some easy walk in the park or they are ignoring that the OP said they want to “both stay in the same zone and same speed”.
I assure you, my wife gets a great workout on her ebike when she wants one by simply turning down the power or shifting the gears. I also own an eMTB and when I want one, pedaling a 50lb bike in the woods is one hell of a workout. When I don’t want to be destroyed, the ebike let’s me go farther and longer.
If the partner wants an ebike, good for them. If they don’t, good for them, there are lots of other solutions mentioned above too. But assuming it’s an insult to offer them an ebike and that they won’t be insulted when you tell them that in order to ride with them at the “same zone and same speed” you have to ride a heavier, slower, bike, put tension on your brakes, and put sand bags in your backpack is just silly.
This is where it becomes patronizing, if the partner doesn’t want one. I’m not assuming an ebike is some easy walk in the park. My wife has one, she uses it on her commute, but it was her choice, not me saying she needed it so we can ride together.
No one said “tell them they need an ebike or you can’t ride together”. It’s just an option.