Remove the Finnish parts and you have the standard American marriage.
She didn’t split because they were so different. Opposites like masculine/feminine attract.
When the sex fell off, what did he say, they rumble one every other month? Typical American marriage when her chemicals wear off. She can love you fully and still use the words “Not IN-love with him”, which is code for I don’t feel desire anymore, so I’m not into sex with you. No, I don’t want to fuk you. You repulse me sexually.
As far as the social paradigm is concerned, he didn’t do anything wrong. He was conditioned and trained properly. That’s what a man’s western training does to him.
Until a man steps out of the feminine imperative he is a robot worker who creates revenue and taxes and more importantly, serves women.