April tries to make trouble.

Amber is right, of course. As it turns out, your weekend inspired suspicion in April’s PI, but he couldn’t get any concrete evidence that you and Amber were having sex. Evidently your house insulates sound just fine, because he didn’t report any screams. When he brought his suspicions to April, she refused to take them seriously at first. However, you made her so angry at the coffee shop that she decided to investigate on her own.

Later that day, you realize what happened. Amber had left her yellow panties lying around—having had more important things than neatness on her mind when she took them off—and while they weren’t conspicuous, they were clearly visible from where April was sitting. It’s bad luck it happened to be those, because there’s very little of Amber’s underwear that April would recognize. Such is life.

That explains the anger in April’s eyes when she left. When you described your new girlfriend as younger and hotter than her with better tits, instantly that unknown woman became a rival—and apparently an intolerable rival. To find out that that rival is her own daughter is a heavy blow to her ego, and in her eyes a despicable act of treachery.

She tries to get you in trouble with the police, since sexual relationships between step-parents and step-children are illegal under the law against incest (even if the step-child is a legal adult). This founders on the fact that you and April were never married. She does her best to argue that your relationship with Amber is incestuous anyway, but it doesn’t stick. A police officer comes out to ask you a few questions, but you get the feeling it’s just for form’s sake.

April also tries to get Amber in trouble with the university, but she gets no traction there at all. Amber’s a legal adult and there’s no criminal case. April doesn’t know about the weekend you spent with Amber on campus, so campus security can play “not our jurisdiction” and ignore the whole thing.

In the last analysis, everything April says comes off like sour grapes. Everyone around you understands “younger and hotter” as clearly as you do, and a happy Amber has a much more winning personality than an angry April, to boot. You and Amber are clearly, radiantly in love; everyone you know thinks you’re cute, and no one sees anything wrong with you sleeping with a 21-year-old woman. Sure, you were dating her mother, but even April has to agree that you were always just a friend to Amber, not any sort of father figure. (After all, you’re only six and a half years older than she is, and you had no interest in being her big brother.)