Honestly, it takes what it takes. Acceptance was a long time coming for me. Oh, I thought I accepted him as he was, but still I continued trying to get him to change. That's not acceptance. For me, crying myself to sleep every night wasn't enough. Him driving drunk with our kids wasn't enough. Hurting the dog in a fit of rage wasn't enough. No one can predict what will be enough. But, when you get there, you will know it. In the end, you have to accept him exactly as he is. Whether you decide to stay or leave at that point is irrelevant. It's the acceptance that frees you.
In my case, I wasn't letting go until I had been sufficiently dragged and psychologically beaten to a bloody pulp. What I see here is not judgement or impatience, but the desire to prevent someone else from going through hell. Trouble is, we all have to go through our own personal hell, otherwise we don't learn the lessons.
L