I want to re-emphasize this point to you, Corey: This is not your fault. From what you have described, it actually has absolutely nothing to do with you. Maybe you can draw comfort from the fact that it sounds like your DH would be the same way no matter WHO he was with. His depression and PTSD are far too much for you to attempt to take responsibility for and be in charge of. You are a good person and wife for putting up with it, for sure, but you are just as much victim of this as he is, kwim?
Again, this is not something you are responsible for fixing, dear. You agreed to be his wife, not his mother or doctor. You agreed to love and support him, not to save him. You can't save him, by the way. You can patch the holes up and build the bridges and put on your happy face, but in the end, he will have to save himself. If you really think abt it, this will be very freeing to you. You are not wrong for wanting a companion or a partner. You are not wrong for feeling smothered and pressured. In essence, he wants you to BE him and do all the things he's too sick to do for himself, and that is wrong. That does not make him better. It just placates him and makes you more resentful.
I am sure that he loves you, or did at some point, but from what you have described, it sounds as if that love and any other good feelings he has had has been swallowed into the abyss of his mental torment. He for sure does not love himself.
I completely sympathize with having a depressed partner. It's so unfair, isn't it? It's so unfair when you do everything you can and everything that is right and what you're 'supposed' to do as a wife and a good person... and it's still not enough. It's so unfair to have to bear the burden 150% of the time, and no matter how much you talk and how many different ways to say it, the other person just refuses to shoulder even one little bit, and you know that you will either have to carry 150% for the rest of your life or lay it down once and for awhile, isn't it? It's so unfair.
I am not suggesting that you leave him. That's a decision you will have to make on your own if it ever becomes a serious consideration. What I am suggesting, however, is that you need to be honest with yourself because he will never be honest with you. The only thing you can believe in right now are the facts, and the facts are that if things continue the way they are now, which is always the easiest way for things to go on, you will always be solely responsible for your marriage. Is that something you want to do? Can do? Would be best for everyone involved?
If you stay, then you MUST invest in a support system of people that you can count on to take up your DH's slack when it comes to the children. Are you involved in a church? Maybe you can set up some kind of babysitting co-op with some other women in your church so you get a day/night off once in awhile? Does your family live close by? I would NOT trust your DH to watch the children for long periods of time, so could you 'trade services' with a daycare provider for a discounted rate? Maybe you could just take in a couple neighbor kids, as long as you were sure your DH wasn't going to be a danger to them, to bolster your income? If you took a job at a daycare center, you might be able to take your children with you to work and see them throughout the day.
Most importantly, you need to get you and your children into counseling. We all know your DH needs to be in most of all, but that is something he will have to do on his own. I know many churches and non-profit organizations offer proated or free counseling. Even a few sessions, especially for your children whom depending on their ages might be really confused as to what's going on with their dad, would be helpful for everyone involved.
I tried to save my ex-DH, too. He was in a horrible mess and so 'down on his luck' and I convinced myself that if I just waited long enough and loved him 'enough' that things would get all better eventually. You know what, though? They never did. There was always another problem, another drama, another complaint, another insult, another argument. I began to see that it wasn't that he was unlucky, but that he never paid enough attention or committed to something long enough to see it through, and when it inevitably turned out the way it would, that would suddenly be his 'bad luck.' It was easier for him to pick on me than to realize he was to blame, and so that's what he did. He insisted I be in charge of the bills, organization, paperwork, etc etc., but also insisted it had to be done the way he wanted it done.
I heard a lot of 'stupid's and 'fat pig's and 'lazy's and 'worthless's in our time together, so I understand that, too, and bought into it for a long time.
And then one day I didn't. I hope you get to that place, too. I really do.
Good luck. It will get worse before it gets better, but then it will be so much better than anything you've ever imagined. Let me know if you need to talk again. You're just an hour away.