at the end of my rope now

I feel like my life is falling apart, I've only recently completely accepted and understood the imapact my ADD partner is having on my life and now I feel devastated why I've allowed this to happen to me.

I am 24, we have been together for 6 years we have 2 lovely children together, they are 4 years and  2 months old. I cannot cope with this relationship anymore and I want out but I cannot bear the idea of him looking after our children for alternate weekends, I don't even think he would be able to be civil with me if we broke up. I'm also scared he would just take the children away and I would never see them again. I also feel that he wouldnt let me go, I broke up with him when we had been together for only a year and he hounded me by phone, text etc until I finally just gave in and took him back just so he would stop. I can't face going through something lke that again.

He works very hard to look after us all but I just cannot live with him anymore. He is inconsiderate and leaves me to run the house. I am at university full time and work part time plus looking after the kids and all this doesnt make me as tired as living with him makes me. I just feel like if I carried on living wth him he would drain the last piece of energy out of me until there is nothing left of me. I am in my early 20's but feel like an old lady, every day is a huge battle and I'm exhausted.

He doesnt understand the huge impact that what he does has on me or the children. I got him to read one of the articles on here and he just looked at me and said "but the problems cant all be coming from me" He is getting an assessment through work next week to get re diagnosed for the ADD as it was so long ago when he was last diagnosed (when he was 16) but im not feeling hopeful about that, we know he has it, he thinks he can just take the medication and all will be fine.I tried to explain that theres counselling etc but he just says "you know I dont like talking"

He does try, he tries to do things to make me happy, gets me presents, takes us out for family days, always making sure the boys have what they need and he plays with the boys lots, he is a great father in that way but I don't know if maybe it is wrong to feel like this but - for me its too late...He only decided to grow up when our first child was 1 year old. I had PND and struggled through that first year while he went out whenever he wanted and stayed out, ignored me most of the time he was home. Theres so many things hes done and I feel those things have damaged our relationship and I just cant forget, Ive lost that feeling of affection for him and I dont know how to get it back.

Lately he has been complaning that we don't have sex ( we really dont very often) but I feel no connection to him, no desire to have sex with him, it just feels like another chore, I dont want to give him anymore of myself, Ive given enough.

I'm just so confused I don't know what to do please someone give me some perspective, I cant cope.