It's just like you say, he is clinging to the past with his teeth, and all along knowing she doenst want to come back..
is this like his first love? cause those are really hard to get over.
I would distance myself from him if I were you for a while. your enabling him
by talking about the very thing you shouldnt be talking about her, but you and him.. she shouldnt even come into the conversation.. you feel sorry for him hes going to keep feeling the same ( sorry for himself ).
he works long hours, so he tells you to bury the feelings he has for her, this isnt healthy thinking. hes basically telling you I dont want to give up on my own so I will use whatever means drinking, work, drowning in something to get her off his mind, but reality is, hes not faced the truth of why she left him and thats whats preventing him from moving on.he has to accept that the marriage wasnt meant to be and if he believes in god and believes in real love he will stop worrying about why she did it and let his heart open up to a new life with you.
and you need to be a lot more firm.. sometimes with some hope, if he realizes he could lose twice, they wake up .. I dont really know what else to tell you , hes the one ultimately that needs to do something.. I give you alot of credit, your situation reminds me of me, except my husband wasnt married.
let me only say this, I let him go, and although we were friends, I loved him silently and the real blow was when he dated one of my friends ( which I warned him about).. after a week the lesson was learned, I kept loving him silently, and even his best friend knew, and asked why, I said I dont know, I just do. and one chance moment we went camping together with mutual friends.. the spark lit up again.. few months later we got together.. I didnt force the spark, it just happened , even though it was always there for me, it was like a awakened dream and I slapped myself a few times to see if it was a dream, but it was real :)
anyways. I hope the best. maybe a step back for a few and let him come to you.
he knows you care, the rest is up to him.