Well, we do know that one can have true love more than once with different people. Harry had true love with Susan, she died, he remain protected until Luccio, they liked one another but because her brain had been tampered with by Peabody's ink, it never became true love. Also because they had sex, it killed Harry's protection from Susan.. Harry and Murphy had true, love, Harry is protected, she is dead, but if Harry refrains from sex for the rest of his life, he should remain protected.