Casanova 70 (1965) on Netflix

Andrea Rossi-Colombotti, a U.N. official and modern-day Casanova, cannot get aroused unless there's danger in sex, but women and society are too compliant, so he's often impotent. A psychiatrist warns him it will get worse, and he should be celibate. Andrea tries and fails at that, abandons his fiancée, finds the occasional life-threatening liaison, and pursues a woman tethered to a dull but murderous husband. Will Andrea find pleasure and fulfillment, or is he doomed to pursue and then go limp when the pursuit is successful?