I think you can honestly say that you've fought long and hard enough hon. I'm so sorry you've had to go through so much. There is certainly a time when one comes to the end of the road and the realization that it is finished, there is no shame in that.
You have done the best you can. And Cat--your best is good enough. You have displayed an amazing amount of strength, dignity, forgiveness and unconditional love. Perfect? No. But extraordinary nonetheless.
I don't blame you for just wanting to get it over with, and in a way, there is relief in being able to step off this rollercoaster and hopefully leave it behind forever (well, as much as possible). I pray that it will be as clean and free from further pain as it can be.
Hold your head up high. You are a stellar person and I agree with Sara that you will be much, much happier in the future.