This isn't going to be an easy thing to do in my opinion, so you need to go into this situation resolved and with firm reasoning. Witnesses are trained to overcome any objection and are very good at it. I wouldn't be suprised to find someone in your situation who wants to make a clean break from it all to still be studing/attending meetings a year from now and not quite know what happened. They can be very overwhelming in overcoming your protests, and they LOOOOVE guilt, which can be a strong thing to argue against. So my advice would be to be firmly resolved, have your reasoning in line and absolutley refuse to have further contact with these people, even if they say it's to "Just see how you're doing". In my experience this was a tactic used to try to worm into a persons confidence again. Other than that, good luck! I really hope it works out for you, and I think you made a great decision.