What is the origin of the idiom "rob the cradle" and when to use it?

The idiom "rob the cradle" originated in the early 19th century and draws upon the imagery of a cradle, which is a small bed for an infant. The term "rob" in this context conveys the idea of taking or stealing something that belongs to someone else. This idiom is typically used to comment on relationships where there is a significant age difference between the two individuals involved. It often carries a negative or judgmental connotation, implying that the older partner is engaging in a relationship that may be deemed inappropriate or questionable due to the age gap.