Antonia, Don't beat yourself up...I lived w/my PA xh for 25 years and never quite understood what was going on w/him until after he left!
Bea, I believe you are spot on about the abandonment. A memory popped into my head when I was reading your posting. When my xh left, he told his mother that I was just like his father. Well, I'm not...I haven't been married 5 times or cheated on my spouse(s), I never went to jail for not paying child support, nor have I stole from my employer or run from the bill collectors. I also never abandoned him, but his father abandoned the family pretty much from a very early age and his mother put up w/him coming back and leaving many times until they divorced when my xh was 16. His father didn't have much time for his kids, but when he needed money, he always made a point of contacting the family for money.
The only thing that I can think of is that my xh knew I was advancing up the ladder in my career and he realized that because of his PA behavior, I was doing more and more around the home and didn't ask him to do anything. Maybe he thought I had abandoned him emotionally...but that's water under the bridge. My neighbors have said that it's like everything has continued to run smoothly at my residence...why? Because I use to have to do it all even when he was here.
Bottom line, PA behavior can drive you to the point of questioning your own sanity.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.