Under-appreciated, under-rated gem
If you think it's a simple task to write a domestic comedy on such simple lines you better try writing one yourself. Then, you need top-notch actors who can do comedy as if it were drama and a director to direct them.
Then, you need a script that's believable, charming, and full of humor with plenty of room for the actors to "do their thing," where called for.
This film has all of that in spades.
Like I said, a gem.