Welcome back internet enthusiasts. Most things in life don't last forever; though we like to fantasize about eternity, even things like marriage aren't eternal for a lot of couples. It's a hard pill to swallow, but eventually it's for the better. But the thing is, you assume it is eternal when you marry the person, so you're probably willing to do whatever you need to do for the sake of the relationship to work. This can get tricky with a decision like a vasectomy, where usually it's reversible, it isn't always.
That brings us to the Reddit piece. This man got a vasectomy because his wife doesn't want any more children. The only problem is that they get divorced not too long after his surgery. It was an amicable split, but what added the hard feelings was his discovery that he can't reverse his vasectomy; he can never have children now. I don't blame him for approaching this from a resentful point of view, but there's no reason to bring the child into the mess.