I recommend you stop reading at the end of chapter 24. Don't read beyond that. The anime stays true to the manga, so the anime is great, it stops right at the 24th chapter, the anime is right-on, they had the right idea using only the first part.

The first part is a truly heart warming, touching, well-developed story of the struggles of fatherhood. It's really nice, I loved it so much and recommend it to anyone.

The second part, after 24, involves a timeskip, and sinking deeply into... A totally different series, really. The mangaka clearly decided to take things somewhere else, and while perhaps she could have made a different series, it feels wholly wrong with the flow of the first part. It's just too much, and it comepletely sours the feel of the first part.

Seriously, just assume everything after chapter 24 doesn't exist.