What is the ruling on a love relationship between a married man and a married woman?

Islam does not approve of any relationship between a man and an unrelated woman outside of a lawful marriage. It has blocked every avenue that leads to temptation, by prohibiting seclusion and enjoining lowering the gaze. This indicates the prohibition of love in the commonly understood sense today. Its prohibition becomes even stricter if the man is married or the woman is married, due to the corrupting consequences that arise from it, such as corrupting a wife against her husband. The Prophet, peace and blessings be upon him, said: "He is not of us who incites a woman against her husband or a slave against his master." It is obligatory to sever this relationship and repent from it.