My speculation is that MC's son didn't cheat, instead it should be a big misunderstanding.

From how he is presented, it seems he is very genuine to his wife, it just that he is more patriotic. It's not like this is bad, after all when you marry someone actively supporting the country, be it soldier, fire fighter, police or even a doctor, this is something expected to happen.

What likely happen is: amnesia, mission or other misunderstanding excuses like the preggo lady likes the son and taking advantage of his kindness to guide her to the obgyn. It's weird but this stuff normal in this kind of melodramatic story.

Her son went missing after a mission and was finally found and sent to an hospital. Even a tiger mom would have felt something, while MC just remain indifferent and "well he is my son".

At the same day got even mad at him for slurping and eating loudly, like dear what. No wonder he is traumatised by you.

I have a strong opinion that how a person view their parents is up to them.

Sure you may think their parent is nice and kind, but you have to understand that unlike you, they have to live with their parents since they were a baby and how they react and behave is 90% base on how they are parented.

in short, just because you had a good experience does not mean you cannot deny them for having a bad childhood.

Heck, the number of cases where the parent is sh*t but treat their child's partner normal is also high. And yet many people still hold this old value that child should let go because ultimately they are the one who gave bith to them haha.