His wife Clytemnestra (Helen's sister) was having an affair with Aegisthus, son of Thyestes, Agamemnon's cousin who had conquered Argos before Agamemnon himself retook it.
A súa esposa Clitemnestra (irmá de Helena) tivo unha relación con Existo, fillo de Tiestes, primo de Agamenón que conquistou Argos antes que Agamenón retomáseo.