I used the fact that relapse seemed inevitable as an excuse to relapse. Any excuse would have done the trick, but that one was the most prominent. I do, however, think you can quit the first time if you're conviction and maturity level is strong.
Get into a program and make sure you learn as much as you can about relapse prevention. Even if you don't have any symptoms now - learn them. Early identification is key to stopping relapse.
Good luck.