Other night she had thumb in her mouth, fidget spinner in the other hand, so I'm chalking that up as a fail
They're pretty cheap ($5 or so), so it's a pretty low cost experiment if your wife is curious
Try epoxy instead; it's slower to cure and smells funny, but produces a much stronger bond, and doesn't have the same problems bearing mechanical loads. I like J-B Weld and J-B Kwik, which are strong and resilient as hell (you can fix tractor engines with them!) and double as a low-temperature casting material for additive repairs, but for what you're dealing with here, the cheap Loctite stuff on the drugstore blister card should do you.
[1]I try to spend as much time as I can teaching my niece how to make things. She had a spinner, and j wanted to show her that she could easily just make one too.
Fidget spinners seem worse. You just hold it and it spins. That's not what "fidgeting" is, since you aren't constantly moving. I don't think it would work nearly as well. It's not supposed to grab your attention, it's supposed to help you keep focus on something else.
I bought one for my son. He's not so interested (he still has small hands which doesn't help). Turns out I use it every day.
See also the glitter bottles I built with him. He liked making them - lots of mess - but I'm the one who spends time watching them.
A lot of ADHD kids spend too much time getting schelped around and don't play well. If you ever volunteer at school you can see it when they are young.
Reminded me of active dogs who don't get walked. If needs aren't met, they adapt in weird ways.
I love the fidget cube though. (Got it from antsy labs)