Adultery?
That would be the 6th by the more standard way of reckoning.
I suppose you lump your neighbor’s wife in with his donkey.
You’d think with two commandments devoted to the sins of the flesh, people would get the message, but no.
By Catholic reckoning, the Seventh Commandment is “Thou shalt not steal”; “Thou shalt not commit adultery” is the Sixth Commandment.