New and losing hope

My husband of 23 years  has ADHD I have four children, the arguments are constant and have been for 20 years. I can't cope anymore, it's so many things. What seems like lies, what feels like he doesn't care about me or kids things because he doesn't follow through makes wild promises, and let's me down so much. I can't stand anymore arguments the pain inside is intense. Please someone can you show me where to start ? 

Thank you so much