Have a weak spot for (someone or something) phrase
To feel attracted to or be fond of a particular type of person or thing in a way that does not change and continues for a period of time.
I have a weak spot for this movie. I've watched it countless times and haven't got bored with it.
John told me that he had a weak spot for women older than him; in fact, none of his ex-girlfriends were younger than him!
The verb "have" must be conjugated according to its tense.
The origin of this phrase is not clear.