What do i do when an under age child is saying i had with him?

I'M 19 YRS OLD I LIVE WITH MY BOYFRIEND AND MY LIL GIRL.. WELL MY NEXT DOOR NEIGHBOR WHICH IS 14 YRS OLD WILL COME TO MY HOUSE TO CHECK HIS MYSPACE THEN HE WOULD GO HOME.. HE'S A BAD LIL BOY HE HAS A FELONEY FOR BREAKING IN TO SOMEONE'S HOME WELL HE'S ONL HAVE BEEN COMING AROUND FOR ABOUT 2 WEEKS. WELL RECENTLY SOMEONE HAS STOLEN MY BOYFRIEND'S X BOX AND WE HAVE LIVED HER FOR 8 MONTHS & NOTHING HAS NOT BEEN STOLEN FROM US UNTIL HE STARTED COMING AROUND HE'S THE ONLY ONE THAT KNEW WE HAD AN X BOX.. WELL EVER SENCE MY BOYFRIEND STARTED ACCUSING HIM HE IS STARTING TO SAY THAT WE HAD SLEPT TOGETHER AND I DONT WANT IT TO GET REPORTED FOR SOMETHING I REALLY DIDNT DO..... WHAT DO I DO ???? PLEASE HELP ME!!