Legal remedy for getting parents divorced for their bipolar behavior

To whosoever it may concern, I'm 17, and for the 17 years of existing I've only had the luck of seeing bipolar episodes of my parent's marriage. I write this as my parents are stuck in an endless cycle of bitter hatred and period love. Their conflicts often take a very drastic turn which happens to have a negative impact on me and my sister. I've been personally affected as a person, I dont wish to see my sister growing as one too. My parents remain distant and their mental state can be a marked deteriorated one.I only wish to know if there's any way I could probably approach for a legal help. Regards.