Ana
An interesting post not least since we don't have too many posts from key holders, especially female keyholders of chastised males. What you describe, however shouldn't be too much of a surprise. It is reasonable to suppose that willing wearers of chastity devices who have given up their keys, enjoy submission. I suspect their personalities are such that they get pleasure submitting to certain individuals and once they have found a willing keyholder, they enjoy a role that can be kept private. While it is tempting to believe that their behaviour changes purely to obtain sexual relief, I suspect it is more complicated.
More likely is that they actually get pleasure in behaving in a private relationship that would not normally be socially acceptable, or at least, acceptable in their own minds. Locked chastity however provides an excuse for them to behave towards an individual (their keyholder) the way they really enjoy, at least subconsciously. It provides a pathway for them to accept their own behaviour while at the same time keeping it private. A path them allows them to enjoy their secret pleasures with the freedom to not make decisions and rely on someone else to guide their relationship. Giving up responsibilities and allowing others to take control is actually quite a relief for some.
It matters not that society would frown on such behaviour and possibly punish them. Morally and ethically all that matters that no one is harmed by this behaviour. That both the chastised submissive and the dominant keyholder enjoy their roles and lifestyle, that is all that matters. Thus, neither of you should feel any guilt for what you both want. Whether you keep your bf locked up four hours or four months is irrelevant. My only concern would be that you keep the discussion actively open, discussing your own enjoyment of controlling him and making sure that that is really what he wants. If he shows any sign of unhappiness, the responsibility is on you to detect it and correct it since you have accepted the responsibility of power over him.
Clearly, the two of you have developed a relationship of unequal power sharing. You are in charge. But think of it that you are really in charge of both of your happiness. It could well be that you enjoy punishing him and there really is nothing wrong with that, so long as that is what he wants too. While he might not relish being locked away for four months, it is likely that he enjoys you having that power over him. My advice would be to use that power wisely.
It is also your responsibility to see that his health does not suffer and that what ever devices you secure on him do not cause physical or emotional harm, even though he wants it. You are directly responsible for things that he no longer has control over. This includes damage to his prostate if it is not “milked” periodically.
From the little I have read, you are not the first woman to observe the effects on a chastised male, nor to relish that power over him. In the end, life is for enjoying and providing you remember and keep faithful to maintaining his happiness, then that is all that matters.