Try not to humanise Henry, as that way you will feel guilty about the whole scenario.
Think about it from Henry's perspective: he will not have the birds and the bees on the brain at all times, will not feel too aggressive towards other cats, will not be impregnating any lady cats (if he's an outdoor cat, of course!), he will not be living in a constant state of sexual frustration.
Instead, he will be fairly relaxed around other cats, won't be constanly worrying about other males trumping him for mates and will be happier and healthier once the 'plum fairy' has visited.
He'll be fine, I'm sure! Fingers crossed he forgives you
