In real terms, I suspect, what made them announce this as they did was like a very real and typical DIL-doesn't-like-inlaws spat.
'If they say one word about me when we return, that's it, I want us to release a statement saying we're out!!!'
Somebody said something, or she read something that she didn't like and so she then spat her dummy out of the pram and said 'Full steam ahead' to whoever manages her Instagram.
It's real life played out on a royal scale.
I think Harry is smitten and in love. I think he really loves her. But I think she's older, wiser and crueller than him. She's cold and calculating. She wanted to be top dog and could not STAND being in the chorus line. They are so badly matched it's lunacy in a way. She's a dominant character, who says nothing in public but uses the machinations of her PR company to extoll whatever rant she's having on any given day.
Woe betide Harry if they ever do split up (which I believe will happen within 2-3 years). She will use the baby as a pawn and be an absolute nightmare to deal with.
She has him on her turf now and if ever there was a living example of the hen pecked husband - Harry is it.