you have a western value set. you are seeing this through western eyes.
thai girls think totally differently from westerners. they have a totally different conceptual framework.
I think that this could best be summed up in this way "if you were making love to your Thai wife and you died suddenly, she would roll your naked body in the carpet on the floor after having taken the wallet from your jeans on the chair and then leave the house in search of another man without shedding a tear".
again you see this through western eyes, from a wealthy perspective and a culture with social welfare protections.
thailand doesn't tax people. it also has no welfare protections. you are free to get off your bum and go out and strive for a future. you can cook and sell food on the side of the footpath if you want.
a thai is free to do this. if they don't try to derive an income there is no social welfare to fall back on.
so this results in a girl having a buddhist outlook on life knowing that if she wallows in self pity she gets nowhere.
they become quite self reliant. added to this the typical thai chap is a bit of a slacker and can't be relied on, they don't handle pressure well at all.
so the girl leaving the house in search of another man is just a girl reacting quickly to adversity. these people have seen huge amounts of adversity in their lives and they just stoically get on with life.
it has taken me many trips to thailand in the company of local residents to even half understand their mindset.
I quite like them. the thai are a resilient people just doing the best they can in the environment around them.
so my tip for slasher is stop thinking like a farang, stop expecting a hundred year relationship, live the way the thai do and enjoy life while you can.
(do keep that secret bank account though as a backstop).
btw thai girls shed tears but probably in private. saving and maintaining face or respect is a large part of the culture.