My ADD husband left me, how to I get him to open up?

I am a stay at home mother of 3 children age 4 and under. That alone is exhausting and can make me lose my patience easily by the time my husband- when he lived here- came home from work anytime after 8pm. He works weekends, with every other Sunday off and one day a week. Whenever he had a day off he would golf or just sit and watch tv, play with his Blackberry, anything but me. Now he has decided he wants a seperation because "I don't know." or for my happiness, that I deserve someone who will love me the way I deserve to be loved. I seemed miserable, I was but I wasn't. I just felt unloved, unimportant, lonely, along with being tired from the kids and housework. I took lots of things out on him. I wish I had come across this site earlier in my marriage, so I could understand that all the times I felt unloved could really have been an effect of the ADD and he wasn't as selfish as I thought and everything I had been feeling was normal. Some of the blogs express my feelings much better than I ever could.

His history is that he had been diagnosed with ADD as a child and was on medicine until he was 17 when his mother died and didn't make him take it anymore. He is just now- after 6 years of marriage- taking steps to as he says "fix" himself, but will not let me support him. He will not talk no matter how hard I try, not willing to try anything my way. I think he has just convinced himself he is done. I have tried journals, I have gotten 2 emails in a month that both could be summed up as he wanted to leave. But still no real reasons why.

I have no idea what to think. I know that despite everything that drove me crazy about him, I loved- and still do- him and the man he is inside. I do not want a divorce, I want to work on our marriage, I need to learn not to yell because no matter how loud I yell I will still feel unheard. I know we both have our issues we need to work on- and we are both going to counseling individually- but not for our marriage- as he is unsure if he is willing and able to put in the effort needed to save it. I need answers that he can't give me and that is frusterating, to which I feel the need to keep telling him I am here to support him and love him in hopes of getting something back. It's not working. I think I am making it worse but I need need answers. He was the first man I ever completely trusted and for him to do this to me, I feel I at least deserve to know why. Does he really not know?

My therapist has told me I need to put my foot down and not let him be the one in control of my marriage or my life, which I agree with; I just don't want to feel as if I am abandoning him either. He said he just wanted me to wake up one day and realize I was better than him and to pack up and leave. But I'm not like that. I didn't marry him for only the good times. I knew who he was when we got married and that person is who I fell in love with and still want to spend my life with. I have told him all of this and still nothing.

I don't know what is his ADD or what is part of something else- his self esteem took a huge hit when he lost his job a few months back despite getting a new one- or what part is actually me. Do I walk away? Do I stay until they figure out his meds and hope they work right away the first time and he is willing to work on changing his behavior? Or has he already walked away for good? I just feel so lost any advice would be greatly appreciated. Thanks in advance.