La mujer fue acusada de convivir con su marido en el marco de una relación bígama.The woman was accused of living with her husband in a bigamous relation.
This means that the noun can be masculine or feminine, depending on the gender of the noun it refers to (e.g., el doctor, la doctora).
Después de estar casada con Fernando diez años, Eliana descubrió que era bígamo.After being married to Fernando for ten years, Eliana discovered that he was a bigamist.
