Will he eventually stop?

K plz dont give any smart responses to me i really need some advice. I am dating a boy he is new as of like a lil over a month ago... When we started datin i found out he smokes "weed" he said he would stop for me because i have family problems with drugs and his mom is in rehab for it we both dont really have our fathers they left when we were about the same age..Anyways he promised he would stop, but i found out and he admited to smokin it when we were datin i want to give him another chance but ppl keep tellin me he is still buyin it so i dont know.. Will he really stop or should i get out of it before it just gets worse. Do u think he cares bout me or if he cared he would have never done it in the 1st place?