I can understand him having been homesick and wanting a return to some semblance of a country he knows.
I can well imagine her disliking it, but accepting that if he and the children get sprinkled with the royal fairy dust again it ups their ante back into the higher echelons of society that she so craves.
But one cannot change the past. They cannot unsay and undo the damaging things they have both said and done. There's a lot of evidence that was not complimentary to the royal family, specific members of that family, this country, the media, etc etc. This simply cannot be eradicated and will follow them both for a considerable time, if not forever.
They don't heed sound advice or behave in any logical manner, so presumably it's just going to be the next chapter of their lives conducted with them doing things that attract media attention, whilst at the same time asking for privacy, whilst also wanting royal protection, whilst also wanting the royal association, whilst also needing to earn mega bucks commercially and on and on it goes.
Just back in the UK.
But they are hugely tarnished and many are wary of their motives and dislike their past actions. You need very solid, loyal friends with many years of friendship under your belt to be welcomed back into the fold.
You may have a loving father who happens to be King, but there is also the wider family issue as well.