It seems that an internalized sense of morality is not universal.

I am close friends with two brothers who were victimized by the same woman. She had several casual flings with one brother over a series of six months; which involved kissing and petting, but never sex. Then, as a crime of opportunity, she got drunk at a party with the younger brother, and went all the way with him. Naturally, the first brother was pissed off at what his younger brother had done, but the woman’s sheer ignorance, lack of respect, and absence of morality soon removed the wedge that was stuck between them.

“Have I done something wrong?”, she wrote to the younger brother whom she had slept with.

“It seems like you and your brother don’t really want to talk to me or hang out with me anymore”.

Naturally, both brothers left it for her to figure out.