Old man's darling

Better to be an old man's darling than to be a young man's maid. What does this proverb mean?

If a young woman marries an old man, he will be so grateful that she will be treated well. Like a queen. But if she marries a young man, near her age, he will not value her and she will have to serve him. Like a maid.

The version of this I have always known is "than a young man's slave". My dictionary of proverbs says that it appears in this form in a book called "A Dialogue containing the Proverbs in the English Language" by J Heywood, published 1546.