Pretend you don't care. Say it's a relief not to have to feel guilty about your affair anymore. Keep tutoring her. Make sure she fails. Whenever she comes for lessons introduce her to your kids as the woman daddy left them for.
oh my god. this is the first time I've read an FML and really felt bad for someone. there is no excuse for him to do such a thing and, in addition, leaving a note!?!? ugh. I'm really sorry about that. FYL