I can't believe that bitch cheated on you sweetie, and with your teacher of al people, what a slut! It's okay though Don't worry Step-Mommy is always here for you if you need a shoulder to cry on.
I do have a good idea though.
I was thinking What if you get revenge on her and get her back at her own game! You should cheat on her right away. Actually you aren't that close with any other girls are you.. If only there was a female nearby that you could bury your cock in balls deep...hmm this may sound a little taboo but what if we got her back together?
I'm so mad at her too I want to help you get your revenge too so I was think what if me and you fucked and I let you bury your cum deep inside me like that bitch let your teacher. He's ugly anyway so you'll definitely be 1 upping her there.
What do you say Step-Son?