What should i do?? HELP!! Romace emergancy?

ok so i kinda am p.o. at my bf cause he told me i could trust him so i told him something tht NO ONE was soposed to kno...so he text me saying can i tell the one it was bout and i said no...and he was like k. but he actually did tell her and it almost ruined our friendship...the thing he told her wasnt tru. would u dump him or no??