The Twilight Zone (1985) 3x24

Andrea, a plain, shy, secluded girl longs for love. One day, love comes to her in the form of a cat who transforms into the man of her dreams. The man was cursed to become a cat by a scorned woman centuries ago. Unfortunately, the cursed prince is a little more than Andrea can handle, particularly when he starts "catting around". Andrea gets revenge by drugging him and then taking him to the vet to be neutered.