I think that what you described as being the original cause of him leaving, isn't all your fault.
He sounds like the type of man that would be hard to sit at the kitchen table with and discuss serious personal issues or troubles.
Maybe the both of you were sticking your fingers in the dyke to hold back the water, and inevitably it was going to collapse.
You sound a lot more settled in the finality of the end of the relationship. As time goes on, you will realize that what was needed to keep the relationship going, was never there in the first place.
I can clearly see you already putting it all together intelligently, and moving on.
When you begin to really enjoy your freedom and independence again, I hope for you that you relish every moment, keep the past in the past where it belongs, and be grateful that things happened the way they did now, instead of 10 years from now.