Melissa is his wife. I don't specifically remember a scene with his sleeping alone. But could it have been after a fight?
Vic Mackey: "God creates all men equal. Out of the womb, he starts playing favorites."
There was a scene right at the very end, where she said "night" and we clearly saw there were two seperate rooms for each of the parents.
Now whether their husband and wife trying again, or simply a couple who have children together wasnt clear. My take on it, is we know that he's been through a lot, and she's been there with him. He struggled to overcome his addiction and his relationship with the rest of his family clearly struggled. And is still struggling, though has improved since he got clean. She still feels wary, their together, but careful of each other. Neither want to rush into anything, and their both at a stage where they feel they need their own space, yet desire the comfort of knowing someone else is nearby should they need an ear. The reason they stay in the same house I would put down as more for the sake of their children.
I wouldnt be surprised if it was uncovered in a later episode that she too was an addict, who is now clean, and together overcoming addiction is easier. (Its never too late to relapse. I see that episode in the works as well).
I thought the relationships between most of the characters felt underdeveloped, and this scene in particular could have been emphasised a lot more, as it could have given a clearer insight into both characters. But that also would finalise the character relationship, perhaps they werent sure themselves? This way gives a subtle hint as to say "this is what we think now" whilst giving them the ability to change their mind with little confusion.
This is all from my own observations. Not fact, I dont have some insider knowledge or anything like that, so take from it what you will.
I think this is a couple taking baby steps towards a full reconciliation.
the promo showed a shot of them in bed together in an upcoming episode.
So I guess they will end up living a man and wife on all levels eventually.