a man who cheats on his wife.
a man of low morals or character.
man of little integrity.
He cheated on his wife. Pond scum.
A man who has sex with another man's wife.
Exodus 20:14 -- Don't do it.
Leviticus 20:10 -- Physical penalty.
1st Corinthians 6:9-11 -- Spiritual penalty for the unrepentant / reward for the repentant.