One reason you may stay in a recovery group for perhaps too long is a kind of perfectionism where you have too high an expectation of how the group can help you change. You'd then only be able to leave if you accepted the disappointment of not having changed as much as you'd hoped. Reminds me of a Paul Valery line "A poem is never finished - only abandoned".
One thing I like about AVRT is that it's not about personal development, it's just a technique that you learn and so it's easy to know when the job's done.