Well, people are really quick to throw around the lazy word, when in fact there is actually something causing the 'lazy' behaviour.
OP didn't once mention depression, and I'm sorry, but this sounds like a classic case, and sure enough when OP came back, she said OP said he was depressed. So, what to do? Encourage him to get help for his depression, and if he does not, then she takes her next step, whether that is counselling, separating, etc. I am not saying that OP should enable his behaviour, but I haven't heard much from her in regards to actual help or support for his depression. And by help I mean professional help, and not encouraging him to sit on the couch all day and play video games. But in reality, she can't do much besides seek a separation or divorce, if indeed he refuses to get professional help.
I see so many people on the DIS who are quick to say the husband is lazy, loser or no good, yet he is struggling with a mental health issue. Men don't usually ask for help, so by not offering it, and then just walking away, is not the best way to deal with the situation, IMHO.
If it were a wife struggling with depression, I believe that the advice given on here would be much different than we we have seen in this thread.
OP's hubby is depressed, and guess what? He is disengaged from their life, so she has become as well. She may have decided that divorce is the answer, but right now, she will be divorcing a depressed man, and this may not be the real person who she married. I can't give her advice on whether to get divorced or not, but as someone who has lived with this in a marriage, I would encourage her to provide some other options to her hubby to help him through his mental health issue, besides just divorce. And, if she has been dealing with this for years, as she mentioned, then she herself may not be the same person either - is this her true self? does she really feel divorce is the only option? does she still love him?
Now, perhaps the depression can be used as an excuse, as she herself said that she has grown up, and in that case, then it would seem that the OP's mind is made up to divorce.
Tiger