“Moving gives them an opportunity for a fresh start and a new chapter.
“It’s an opportunity to leave some of the more unhappy memories behind,” the source said.
The royal couple see this as a move for the long-term and view Forest Lodge as their forever home.
It will be where they plan to live as a family when the Prince and Princess of Wales become King and Queen.
As with their four-bedroom Adelaide Cottage, it is understood they will not have any live-in staff as they focus on creating as private a family home as is possible.
William and Catherine announced they were moving from Kensington Palace in London to Windsor in August 2022.
They also have homes at Anmer Hall in Norfolk where they spend much of the school holidays and their offices remain at Kensington Palace.
The move to Windsor has been a successful one and afforded them the privacy and freedom that was more difficult to find in London.
It is understood the family are settled and the children are happy at Lambrook School where all three currently attend.
Any work carried out on Forest Lodge will not come from the Sovereign Grant which provides state funding for the monarchy.
The Prince and Princess of Wales are funding the move privately and they will pay market rent on the property.