One thing is for sure , the guy just take you as a sex tool . Another thing for sure , you and your bf wont last long .
If you repent now and really wanna salvage your relationship with your bf , you gotta break off with the guy and MAKE SURE your COVERING UP for what you have done is really PRO .
Just bury it in your memories and start afresh with your bf before IT IS TOO LATE .
Good luck to you =)