Boundaries only work when you stand behind them. Threatening things and not followingn through just proves to the A that you will continue to tolerate his behavior. Good for you for standing behind your boundary. I guess when you have enough, you've had enough. Good luck in your journey. It sounds to me like you have spent a lot of years tolerating your life--imagine how good it will feel to be excited about what the future could bring instead of picturing clear as day the way things will certainly end up if you stay and nothing changes.