I am new here but just could not help commenting. I am in exactly the same situation as you mentally. Fortunately, although engaged, I did not live with him and I did not marry him. We have been apart for 3 weeks and I have been no contact for 10 days.
I suffered immensely for alot of our three years together. He could not communicate, he was lazy, he did not take care of ANYTHING - not for me or himself, he denied me affection, he lied about everything and he constantly betrayed me by putting profiles on dating sites and talking to women behind my back. He is weak and a coward when it comes to participating in anything that doesn't revolve around him. Any single time I have expressed my concerns about our relationship he says nothing and disappears. I have always been the one to run back, dig him out of his own depression and try to make things right. Three weeks ago he did the same thing after I tried talking to him. This time I blocked him every way possible from contacting me, I wrote him an email and told him I would call the police if he ever came near me again and I have done nothing but try to put the three years I wasted behind me. It sucks! I have moments where I love him and want him back and any cost and then I want to strangle myself.
And on a side note - I supported him through 28 days of rehab back in November, and after 40 days he stopped working on his own recovery. He is exactly the same person doing the same bad things and rehab did nothing but keep him from picking up the beer.... which he probably has done again by now. There is no way he could live his mess of a life sober, sadly.
I will gladly keep you company, feel free to email me any time. My heart is with you and I wish you the best.