please tell me that i can be ok

I don't want to leave my ADHD husband, but after nearly 20 years of being married, I am so tired. I'm so lonely, and I feel too old for not yet 40. I don't dream any more, or plan, because I know that even though it's not his fault, nothing we plan will ever come true. I'm so tired of the shame, of our overgrown yard, our disastrous finances, every day that passes with nothing to show except the same old arguments and his promises that he's heard me when I know in my heart, he can't change. He is a really lovely man and very kind and a terrific dad is, but I know now that to be with him means having to get to a place where I want nothing/need nothing & expect nothing and I don't know if i can do that. Because I nag so much, and cry and have almighty tantrums and can't stop comparing our situation to friends etc/ I'm always apologizing for who I am and how I treat him and he always says, don't apologize I'd be a messif it weren't for you. That used to flatter me but now I realise it makes me feel sad and trapped, because he would be a disaster without me. I realize part of the reason I stay with him is because I fear what would happen to him if I stopped running everything, buying his clothes, making his meals, reminders etc. I imagine seeing the house he would create for himself as a single person and of having to drop our kids of there and I know I can't do it. the reason i have no energy is because it all goes on plugging up this sinking ship.

But that means, I am stuck here, feeling so desperately lonely, with no one who really knows what its like to be so lost in a marrige to a "great guy". Everyone tells me I'm so lucky all the time, because he's so forgiving etc but I think it's because he just forgot our arguments. he'll never change. members of his family, and now sadly, one of my own  sons has ADDD, and I feel like I can't escape this horrible condition no matter where i go. It's everywhere and I feel crazy all the time. I so desperately want to run away and start over with a person who can actually love me and make me feel safe and do the things he says he'll do. I mourn all the years of our early marriage when I didn't know he was ADHD. also because i do love him i wish i got to know who he would really be, if he didn't have ADHD. The real version of him is in there somewhere but can never really exist because of this horrible condition. i feel like there is no hope, and that I'm too young to have so many regrets, so much anger and grief. noone in my family knows, a few of our friends I've told but they don't really believe someone like him who seems so together could have that "thing naughty boys have". it's funny how many people on this forum comment on feeling like they have a giant extra child. that's how i feel all the time, and i have so much shame and embarassment attached to that. it's like an entire level of emotional operation just doesn't exist there. i know he feels frustrated and depressed too, and i feel like i am ruining his self-esteem by constantly drawing attention to all his deficiencies and making him feel bad for what he can't fix. i don't even know why i am posting. i guess this is the first time i've realised i'm not alone - even if it's virtual, and in real life, i am truly, truly alone. i even notice i am slowly pushing every real friend i have out of my life, because i am tired of being the woman at my coffee morning who is always complaining about the same stuff which  noone even believes is real. i wish i could start my life over again, i wish i'd had all the information when i chose to get married so that i wouldn't have a sense of being "mis-sold", or i wish someone could invent a cure for ADHD so I could stay married.

thanks and sorry for the depressing post.