I wish my parents would just get divorced, advice needed please!?

Okay, so I'm 16 and I'll be a Junior in High school this school year. So my parents have been together for 11 years. My Dad adopted me when he married my mom. So my relationship with my "Dad" has never been that good. He always says how i refused to obey him and all that crap when i was 5 or 6, and I'm like seriously, the minute i met you, you seemed to want me to treat you as my father and act like I've had a stable life...when I hadn't. He doesn't get that. So my parents always fight, its so dumb, and sometimes its because they don't agree on how one of us (my siblings) gets treated, or punished or whatever. Like my brother is a huge instigator and when he doesn't quit i try to get him to stop and then i get yelled at and told to handle it by my Dad. When my brother acts like a freakin jerk off sometimes. And then my Dad goes as far as telling me I'm a "pretend christian" and "i hate my family" and "ive never been happy" and how "i always try to mess up the family and the marriage". When in reality I'm not the one who's accused my mother of cheating and then threw a freakin yogurt at her "for her yeast infection" wtf is that about. My Mom tells him shes had enough and she deserves to be happy and all that, but then the n ext day my dad sweetens her up and all that and then its like that big blow up never even happened. But then a few weeks later it happens again, my dad refuses to go to a counselor and even a pastor for marriage help, and i feel everyone would be happier if they weren't together. Plus (i've even told my mom this) i don't see any affection from any of them to each-other anymore. My Mom wanted a 10 year anniversary ring and then my Dad makes a big stink about that....it just isn't working and sometimes it gets physical and I cant do anything...i mean whats gonna happen to the 3 other kids in the house when i'm 18 and gone? What should i do? I can't really talk to my dad about this because it'll turn into something else and if i go to mom and she tells my dad i said something they'll just cause more trouble...