I will tell you what I see based on my experience in these things.
He is showing the signs of having another woman in his mind.
This is how men act when they have another woman. He knows he can have you at any time. That gives him all the power. I am sure you have heard "the one who cares the LEAST is in charge of the relationship".. You have allowed him to be in charge. I find this sad to watch when women are in this position. I do know that most of the men that I have ever known in my life have usually only left their wife for one thing. Another woman.
ALL of them? HHHMMM..
I can't recall any that haven't left without one on the side, but I am sure there must be some, because I surely don't want to be known for saying ALL.
I believe you are overlooking that possibility and this is causing you to blame yourself and try to find some possible way to "win his love" back.
Ok? That is my take. I would do whatever it took to find that out before I made any other decisions about which way to take this. I have found though that many men and women don't really want to hear that. They just don't want to believe it. Denial.
"The spouse is the last to know".. is usually true..
Like the quote we heard..
When a man wants you NOTHING can keep him away. Not even Iraq. NO?