Scoundrel in White (1972)

Jean-Paul Belmondo plays Paul, a former womanizer who marries the head of the medical department's "unattractive" daughter Christine because he thinks attractive women can't be trusted and make poor wives. A car accident leaves him bedridden and he begins to miss his playboy days, when Christine's bombshell sister Martine arrives and Paul decides he must have her. He begins drugging Christine at night so he can sneak out to kill of Martine's many suitors one by one.