Well ain't that the truth.
Humans aren't a one size fits all species.
I think a lot, if not most all on here have been previously married in their home country.
People can drift apart, that happens and hopefully not too acrimoniously.
I met my Thai wife at work in Singapore. I'd already drifted apart from my wife, too much travel for work, and i delved into the workplace affair. Not too honorable I'll admit, but it happens.
We aren't far apart in age, and she had grown up as a teenager in Chicago, so we shared a lot of cultural things, maybe with the exception of baseball.
She's a diehard Cubs fan whereas I'm a Giants fan
So on to marriage.
We were OK in Thailand until our son went to college in Chicago and told us he wasn't coming home.
So, only only reason we actually got legally married was to get MrsG a green card
So I don't think the OP's premise is really valid. Marriage in all cultures is an up and down thing.
Maybe cross cultures is more difficult, but in my case Mrs G was a bit of a hybrid so I've never really thought about it