About my relation....is he really loyal?

guys..m in a relation frm 2 yrs...ystrdy i met ma bf n chkd his ph der ws a msg to sme no my bf had msg her.......u wanna meet r nt odrwise m goin.....n the gal replied i m bsy whn i askd him wt is dis he said are i just tlkd to dis gal i wntd her to b ma frnds gf..n said dat i cant tell u her name...i dint kol him frm yesterday neither did he he knows hes wrng ...bt at nite he msgd me dat ...i need a brk up bi 4eva...bt he loves me i m sure bout dat wt shud i do plz reply soon m dying frm insiede plzzzz i dnt want a brk up wt shud i do so that he tells me the truth himself plzzzz help