adultery
adul·tery
/əˈdʌltəri/ noun [ noncount ]
: sex between a married person and someone who is not that person's wife or husband
He found out that his wife had committed adultery.
She accused her husband of adultery.
adul·ter·ous /əˈdʌltərəs/ adj
an adulterous affair/relationship
adul·ter·ous·ly adv
