my boyfriend cheated on me

my boyfriend cheated on me. i’m 17 years old and i’ve been chasing this boy for over 3 years. i finally got him and i saw yesterday he was in contact with an ex sneaky link asking her for nudes. i am heartbroken but i’m not gonna leave him because i love him with all my heart and i really have no one else but him. no friends, and i don’t speak to my family like that. he’s very apologetic but i’m having a hard time. can someone please give us advice on how to get through this together