Good for you for stopping the self-torture. Looking over my own thread reveals that I have gone down that fruitless road (OP) myself way too often.
It is understandable, we are constantly looking for explanations that somehow make sense, even if they are painful. And it somehow makes more sense that a spouse would leave what we LBS's know to be a good R to go to another person. It is so painful to think they would leave to be alone - that being without us is better.
But, they are not themselves. They are shadows of themselves without enough to give. It really helps me to think of my H as fragile, even when he has said hurtful things.