Dictionary of American idioms

VACILLATE BETWEEN SOMEONE AND SOMEONE ELSE OR SOMETHING AND SOMETHING ELSE

vacillate between someone and someone else or something and something else: translation

vacillate betweensomeoneandsomeone else or somethingandsomething else
to waver between a choice of people or a choice of things. •

He kept vacillating between Fred and Alice.

Wayne vacillated between chocolate and vanilla.