it's sick but at least the wife didn't fuck another dude to get preggo. the kid will be his nephew/niece and not a complete cuckoo. the tiniest of silver linings.
The execution is fairly nice. The MC is neither a doormat nor edgy. He gets things done. The girls aren't afraid to express affection for him, either. So there's no pointless drama, and we see the actual plot advancing.
I suppose when you've literally saved a whole world before by fighting said world's equivalence to the forces of Hell, you might get used to how crap people can be.