i want to use this term as someone who is kind of swooned and throw rationality to the wind because of the impact of someone else. Would that expression do?
MOJO means "Sex appeal" or "Charm, spell" Link to definition
Thrown off his mojo means he lost his charm.
So throwing caution to the wind does not have anything to do with mojo.
He went off the deep end when he met her.
A rude way to say it is 'whipped' and even more rude -- 'pussy-whipped'.
pussywhipped(adjective) Submissive to or dominated by one's wife or other female partner, frequently with the connotation that this submissive behavior is for the prospect of sex.
Synonyms: cowed, uxorious, henpecked, under the thumb, whipped