I think you should blame yourself because you are not stay stick with your decision. That kind of friends will be exist all the time doesn't matter if you try to avoid them also. Does it mean you won't be able to come out from gambling? You are disrespected you decision and you know yourself better and what to do.
Nobody can help you if you can't help yourself.
I actually do blame myself and no one else because I believe that all the change I want has to be done by me but yeah, I absolutely agree with everything you said.