Dead Ringers (1988)

In "Dead Ringers," Elliot, a prominent gynecologist, shares his medical practice with his identical twin, Beverly. Elliot's charm leads him to seduce numerous patients, but his fleeting interest results in passing them off to Beverly, who is more reserved and unaware of the switch. However, things take a dark turn when Beverly becomes emotionally attached to Claire, one of Elliot's former lovers. When Beverly unknowingly betrays Elliot’s trust, he spirals into a disturbing descent into madness, unraveling their complex relationship and blurring the lines between love and obsession.