Stepmom knows you should be studying for you classes because you have a big test tomorrow and finds you distracted and arguing with your girlfriend on your phone. She tells you she's a distraction from your studies. What she doesn't know is you peeked in on her having sex with your stepdad and saw how bored she looked. Stepdad is gone a lot for work. You tell her she is just jealous of your girlfriend and she is really upset and tells you that's not true.
Stepmom takes your phone and you finish your studies and go out for the evening with your friends. Your girlfriend ends up picking a fight and you don't get home until 2am. Your stepmom is really mad since you have classes in the morning, but you're upset from the recent breakup and tell her she's just jealous.
The next morning your stepmom says she's sorry about the fight and wants to make you a special dinner to make up for it. You end up fighting again and you finally decide it's time to stop pretending you don't want your stepmom. Your stepdad is going to be gone for weeks so you get to finally have all the special time with step-mommy that you really wanted.