Family Troubles

I feel like my world is falling apart on me while I'm growing up and out of it. Since I'm planning on making a big move soon for a job and love, i'm worried about my family. I'm worried that my parents won't make it. My dad is quite by nature, but battles with issues of depression himself that he does not address. My mom takes on the weight of the world since she deals with my health issues and my elderly grandmother. Both don't think each other is there for them, and don't want to talk or address it unless the timing is just right. When is the right time to tell someone you are unhappy in your marriage. I've always been afraid of my parents getting a divorce, because I knew it was a possibility and never wanted it for myself. I didn't want to be torn apart during holidays and be even more detached from my father. I said i would pick one and disown the other. When i was still in school i said i would use them for monetary purposes only, but now that I'm older I'm not sure I can do that. I feel like if the big D happens I would want to disown both of them and meld into my friends family. I hate the feeling and it gives me a heavy heart to hear my parents talk about each other so negatively. I'm caught in the middle and I don't have anyone to talk about it with because it's personal private information that my parents wouldn't appreciate if i share with my friends. Since my friends parents are their friends too. So since i can't tell anyone, i'm choosing to tell the world in this somewhat anonymous way. So if anyone has advice for me during this gray period with my family it would be appreciated. Thanks for listening.