I don’t see breaking up with someone you don’t want to be with as a failure. I see it as a lovely, loving thing to do.
I think the success/failure model gets in a lot of people’s way — no matter what groups they belong to — or don’t, no matter whether they want to want to fix things and/or understand and/or embrace things.
I admire you doing what’s right for you.
Al-anon — and all twelve step stuff — has been a great powerful tool for many people. I can see by the choice you made — with only one meeting — it worked for you.