It's wrong to have an affair with someone's spouse.
Dean is at the bar where he meets a married woman who is flirting with him.
Dean wants to engage in sexual intercourse tonight.
Dean refuses the woman's advances and instead calls a friend he hooks up with from time to time.
Dean takes the woman home with him, and they end up having sex.
The married woman feels embarrassed by being turned down and goes home instead.
The woman's husband finds out and it ruins their marriage.