A Dama do Lotacao (1978) aka Lady on the Bus
She gives herself to everyone in order to keep loving her husband.
Actors: Sônia Braga
Gabriela (1983)
A man finds his black wife and his caucasian best friend in bed.
Dona Flor and Her Two Husbands (1976)
A wife cheats on her current husband with the ghost of her dead ex-husband.