I can't keep doing this to myself

I can't continue to live like this. Constantly fighting, constantly putting myself and her through this. We fight, it's better, we fight, it's better. I'm so tired of this. my head feels like it's gonna explode. I just don't know how to live without her. We've been together since high school, almost 20 years, almost half my life. How do I go on without her, how is it even possible. We have to daughters (8 & 10) and I'm worried about them. I can't imagine not seeing them everyday, that is gonna kill me alone. But being here is gonna drive me to old habits soon cause I can't handle it. I don't know what to do. I'm in to much pain to even think straight right now. I just need to get out for a bit.