The closer I get to his sober self, the more angry I get when he's "gone." ... at the end of the day, your heart is still broken and you still miss the person and it still hurts... it still hurts lot. And it never stops hurting.
It DOES stop hurting. You can choose to stop the hurt. You can't control what HE does but you CAN control your anger.
I detach with love and go on with my life, my work, my family. But what do I do with the residual pain? ... I thought I loved the rest of him enough to just detach from the rest... but now I find that the more I fall in love with him, the more painful it is when he "disappears."
Stop falling more in love with him. You can choose to stop this. You only have to change your mind about it. You change your mind about it by finding a new way of perceiving the situation.
I think also you may need to do some more or different work on Detachment.
Many people here talk about PHYSICAL detachment to fix their problem of an alcoholic in their life. For me personally, physical detachment is also my preference for "romantic" or "love" relationships I involve myself in with alcoholics or addicts. However, my Dad is alcoholic so my chosen type of detachment there is different. It is much more of an EMOTIONAL detachment. It is difficult to emotionally detach from a parent, but it is not impossible. Lots of people have done it. I think it is quite possible for you to achieve that in a romantic relationship also.
Emotional detachment can start with Acceptance. Which it sounds like you have already accepted his limitations. So, YOU ARE ALREADY ONE STEP AHEAD OF THE GAME!!! You should feel good about that
Next, you can work on lowering your Expectations. Where are your expectations of him perhaps too high? Do you have him on a pedestal? Do you ADMIRE him or look up to him for who he is or what he does when he is sober? Do you expect him to "save" you or take care of you? Do some reading on Magical Thinking. How much of your desire for "romance" and "love" in this relationship is just Magical Thinking? How practical a person are you? Where can you adjust the way you perceive him?
I personally never thought that a "love" relationship with a man where I was fully emotionally detached would even be worth it. But after eight attempts at what I thought was the ideal relationship where I was fully emotionally involved, I have finally found a relationship where I am able to be fully emotionally detached. It is VERY weird, but it is WORKING. For me, emotional detachment means that I am FINALLY able to maintain my personal boundaries (not ENTIRELY, but in large part--still practicing
It means also that I do, for the most part, what I need to do to maintain my peace and serenity at all times. (I look out for me and I do not expect ANYone else to do that job FOR me). It means also that if this person ever starts to behave in ways that compromise my peace and serenity, I will be ABLE to detach from him PHYSICALLY 100% in order to protect my peace and serenity.
I hope something I've shared here is helpful to you.