Concept not my family HD

What is “not my family”? when the guy has sex with someone close but is not part of his stepfamily, like a neighbor, a teacher, a classmate, etc in todays update, peter greens neighbor harley king knocks on his door asking if she can use his wifi to finish some schoolwork when peter catches her watching porn, she confesses that shes had a crush on him for so long and wants him real bad, but peter is married and tells her that it wouldnt be right harley keeps making excuses to come back and seduce peter, and when she refuses to leave until she can suck his dick, peter gives in to her demands and fucks her brains out!