Advice?

So, My parents aren't happy...

Here is the scope, and this is personal I know but it's something I can't really talk to anyone in real life about right now (Cuz its late).

My mum and dad have never really been a lovey dovey couple, they've not been in love since I was small but stayed together for my sister and I.

My father used to work away a lot and my mother stayed at home and raised us, basically like a normal family, but for almost a year now my dad has been home and not working, we were planning to moved to a new house and he wants to start a business in the countryside or something... whatever... anyway!

My mother can't stand my dad and visa versa and my mum want to leave him.. she is technologocally inept... so she'll need my help looking for a place to move while leaving my dad.. but I'm not a person who can take sides... my dad or my mum... plus my sister is still young...

It is hard... I feel like my mum, sister and I are talking about leaving him and its unfair... I just don't know what to do... I love both my parents... and i want them both to be happy... has any one else been through a seperation like this?

Any advise would be helpful because right now this is stressing me out... just because I'm the eldest kid in the family I get the brunt from both side and i don't want my little sister getting too involved...