The Alfred Hitchcock Hour (1962)

S2E12 Three Wives Too Many

Title: Three Wives Too Many Plot: Brown, a compulsive gambler and bigamist, finds himself in financial trouble as his rich wives begin to mysteriously die. The police investigate him for potential murder, but without any solid proof, they reluctantly determine that the deaths were suicides. Unbeknownst to Brown, one of his wives, consumed by jealousy, is actually behind the killings. She threatens him, declaring that if he ever betrays her again, she will take her own life and ensure he is blamed for her death, as well as the deaths of his other wives.