Most kids are born for selfish reasons. "I want a kid", "They're lonely, we should have another one", "it's a boy, I'd also like to have a girl" ...
And especially in those medieval times, another kid meant more working hands for peasants and more political alliances for nobles.
Doesn't mean they're not loved once they're born.
Was Billoy ever loved before the stupid MC decided that magically she can love the kid now? That amount of trauma can't be healed, even she did love the other two kids you can't deny that what she and the ML did to Billoy was trashy to say the leastm also there is the fact that neither of them shpuld have any kids when they are such a mess to begin with. Every kid deservs a parent but not every parent deservs a kid.
Nice so he used his first kid as an excuse to see her, didn't knew about the second kid until she was OLD ENOUGH TO RUN AFTER HIM, and now he had a third kid just to have an excuse to visit her in autumn.... these kids sure gonna end up as healthy grown ups.