i cheated on my partner

hey guys, so like yesterday was a real turning point for me. i teach high school but i got all these fantasies and they've been building up for weeks now. today at work there's this student who's in her twenties she's super into me and has been making moves since day one. we finally ended up alone in the storage room during lunch break, and it was intense. her hands were everywhere, exploring every inch of my body until i couldn't take it anymore. i pushed her against a stack of books, our clothes flying off faster than you can say go. i felt her wetness the second she was naked, rubbing herself on me like there was no tomorrow. we kissed deeply and then she took me in her mouth, oh god, it was so good. i returned the favor when we switched positions, guiding her onto my dick and pushing deep inside her warm tight hole. our movements were frantic but perfect, slamming into each other until we climaxed at almost the same time. afterwards i felt guilty, scared even, like maybe i should tell my partner or leave teaching. what do you think? is this normal? am i a bad person?