Dealing With Issues - Why Can't I Just Let it Go?

I am on the edge of a cliff facing the great abyss, the chasm of the long goodbye. Every time i feel like I will handle it better this time, I'm more prepared, I can DO this. Yet every time I feel engulfed by all the same emotions: despair, hopelessness, loss of control and so much more. I feel like there are so many emotions bottled up inside me that if I have to deal with just one more, I'm going to explode.
In order to be prepared to do the things that I am going to need to do, I have to first deal with my own issues. Sometimes I feel at a loss as to how I will even do that. At times I feel so overwhelmed that I grasp for even a place to start. I guess I have to come to terms with my own issues and my own feelings first before I can deal with other issues or help others with their emotions.
So here's the thing. I'm hurt, devastatingly so, and I'm angry. I have all these emotions pent up and memories from last year that I thought I had dealt with and moved on from which are apparently still there somehow, like a splinter in my heart that is just festering.
I have all this anger - rationally I know that I shouldn't, but I do. I feel angry that my husband is leaving, even though I know that this is out of his control. I feel angry that so much of our time is shared and we have so little of it to begin with, and worse, I feel angry when he's tired all the time. He makes an effort to spend time with me, but honestly it's like being with a zombie - someone who is only half there. I sense this and I get mad. I get mad because I feel like I shouldn't have to feel second best or take second place, though rationally, I know that for right now at least, I must.
Do you see my conundrum? I GET that what I feel isn't right, isn't rational, but I can't stop feeling it and I can't change it. I WANT TO CHANGE IT, but I just don't know how to let all these feelings go.
Every cruel word - even those I know he didn't mean - they all weigh on my heart. Every careless comment like how it wasn't "worth it" for me to travel to see him, they each weigh on my like a planet of pain and regret. As I said in the past, I know that my man is not the "throw caution to the wind" type, but once, just once - because he loves me, I wish that he would.
I pour my heart out, in letters, in pictures, in blogs and I wonder: does he see? Does he know? Does he understand that it kills me to watch him walk away? Especially knowing that my job is to watch him go with a smile on my face. It seems like an impossible tasks.
How can I let these feelings go? How can I take the anger out of my life that is eating me and my marriage like a poison from inside? I just don't know the answers and I feel like I'm just groping in the dark. Still, I keep searching for a way to find the light. Any thoughts? Suggestions?