Chris' secret desire to be dominated and treated like a baby had been a secret from Cheryl, his wife, for many years until the day she, as his business partner, queried his business expenditure. Chris' world collapsed that day from being a successful, well-travelled businessman to that of a child, imprisoned in his own home - a victim of his desires.
Cheryl decides that rather than be stuck at home with a baby - albeit an adult one - she could do with some help to humiliate, belittle, and degrade her husband even more. Pretending to be a baby and being made to live as a baby are two very different things.
A Gilded Cage can also be a baby's crib