i am glad that you are at least acknowledging that you have depression and that you are taking steps to see someone for this punk. That is absolutely the right thing to do. It may need to be medically managed.
I also really dont think you are being attacked, and its a shame that you feel that way. All is see when i read the posts that you may not agree with, is a wealth of well intentioned and sensible advice.
I also have a 23 year relationship, which has produced two children - my DD is the same age as yours, my son is 20. I understand the desperation to hang on in there, but what you have done is invested the whole of yourself in your husband. He shouldnt be your reason to live, or not.
You still appear desperate to please him, desperate to defend him, when he has for what ever reasons, done wrong by you. He has chosen one hell of a time to go and find himself in counselling....of course he will have had his own pressures and problems to deal with, but he hasnt done any of this the right way. Not many people just bail in such a cowardly way, with no warning. correct me if im wrong. This is why his actions have prompted such reactions from others, your friends, your neighbours - you are the only one reluctant to acknowledge it because you still want to defend him.
I understand why you felt desolate. This time of year is a bugger for anyone with depression, and you do have depression, which like you say, is understandable. The important thing is that you acknowledge why, recognise it, get treatment for it.
It wont make all the bad things go away. But it will restore a sense perhaps of some perspective.
You seem "scared" to allow yourself any anger in your husbands actions. Do you think that if you tow the line, be a good wife, simper and soothe him he will come back? (ask yourself) You should be allowed some anger at him. Anger would be normal.
what about couples counselling? i think you both need to be honest with one another - and i dont think thats happened yet on either side.
I am truly glad that you have found some resolve to keep on living, being a mother to a daughter who needs you. You are so much more than just his wife.