Be swept off (one's) feet phrase
To fall in love with someone quickly and strongly; to become greatly admiring of someone; to be particularly impressed or charmed by someone because you have a very strong feeling of love for them.
I was completely swept off my feet at how attentively he treated me.
When he poured his heart out with a confession of love, she was swept off her feet.
He was swept off his feet at her exotic beauty.
Wholly enamored (of someone)
This phrase dates from about 1900.
People tend to like forbidden or illegal things just because they are forbidden or illegal.
He must have believed that stolen fruit is the sweetest, and he, therefore, cheated on his partner.