If there was one couple from the show I expected to get divorced, it was Minh and Khan. More so than even Nancy and Dale. Not that the original series failed to give them redeemable qualities or show that they some good structures in their marriage, but it was clear that neither one was healthy for their own good. They were always they stereotypical asian tiger parents forcing too much onto their own daughter and were obsessed with obtaining high success in life. It isn't shocking that they burned themselves out eventually. Especially when Kahn was shown in the original series to easily fall to the toxic influences of others, often having to be reeled back into sanity by somebody of a more positive influence.
I can envision them both being unhappy and just putting on a facade until their only child left the nest to become an adult. It is why I don't fully find Connie's character development in the revival to be so far fetched: she comes from the exact unhealthy background that would produce a person that would do stuff like that.