Jenna This has always been a tough issue for me here on the forum to defend myself.
That is pretty much a struggle that will stay with you as long as you are simultaneously function as a natural authority figure, as a keyholder and as the person who introduced the chastity belt. As long as you are holding the keys of your dependents when the chastity belt was your idea, there will always be a subconscious level of non-consent in your dynamic, whether you want that or not. Even if you make it clear to them and to us that you would love them just the same with or without the belt, they know the belt means a lot to you. And as their surrogate parent, your relationship with them is inherently unequal. That inherent inequality will always be at odds with the idea of freely-given consent, thus as long as you stay in this role, you will not be free from the struggle of having to affirm that they can freely choose over and over again. The only way out of that is to let them freely manage their own keys.
To be fair, I do like all the effort you are putting into making sure things are as consensual as they can be under the constraints of your relationship with them and your expectations of the belt. And I certainly hope some of that rubs of on Monica.