have a weakness for
Be susceptible to; also, like or enjoy. For example, She has a weakness for older men, or Bill has a weakness for fine wine. [c. 1700]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.