@Valanway It's not about the person wanting their partner to be happy after them dying, it's about how much value the other person gave to their love, and in return, how much love that person actually had for them. Being divorced and dying are two very different scenarios. The latter being one which you have no control over, and the former being a conclusion reached after careful consideration from both parties (usually).
Sure, his daughters' behavior toward him was unjust and wrong, but she's a teen, she saw that her father wasn't there for her Mom. Even if he had work or mouths to feed, it doesn't mean you aren't there for your wife when she's literally on her death-bed. Which brings me back to him actually loving his wife or not, because if he really had a genuine affection towards her, shouldn't he have been shown reminiscing the memories they made together, for example, whenever he's with Koto? You know, get reminded of what was lacking? This leads me to one of two conclusions; one, his wife didn't give him the love he needed or two, he had no time for her love, in which case, there's no one to blame but himself.
See, although my problem is with him being shown to love someone again, I can move past that. I also have a problem with how he reacts to someone giving him love, and how he loves them back. It's as if he has never loved anyone before. That's what bothers me. Yeah, it's his biological needs but still... (I think you're talking about that time when he let himself go in the cafe but Koto luckily passed out, because aside from that, he has so far controlled himself.)
But, at the end of the day, this is just a manga with fictional characters. Without reading between the lines too much, even I want him to be together with Koto, and for his life problems to somehow get resolved.
[I'm pretty sure this whole thing is a mess, and that's probably because I'm sleepy af rn lol. I'm sure you understand the point I'm trying to get across.]