1
general::
Phrase(s): have a weakness for someone or something
Fig. to be unable to resist someone or something; to be (figuratively) powerless against someone or something. • I have a weakness for chocolate. • John has a weakness for Mary. I think he’s in love.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
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]
American Heritage Idioms