Article continues below advertisementAl Pacino is reportedly heartbroken over the passing of Diane Keaton.Article continues below advertisementThe 85-year-old actor, who dated the Oscar-winning actress on and off from 1971 to 1987, "will forever regret he didn't make his move when he had the chance," a source revealed, adding that Keaton once gave him an ultimatum to "marry her or else."Article continues below advertisementSource: MEGAAl Pacino is allegedly mourning Diane Keaton's sudden death.