Many teens really believe that their parents will get back together. They try very hard to make it happen by being on their best behaviour.
Sometimes this is a way of denying what is really happening, in order to protect yourself from the painful reality.
Chances are, your parents reached this point only after trying very hard to save their relationship, and their decision to split up is final.
It's hard, but it's probably better for you to begin to accept the situation as it really is, and get used to the changes that you are facing, in order to get on with your life.
Ideally, your parents will make the decisions together about who you will live with and how that will work. Your opinion should be taken into account.
If they can't decide themselves, they might go to a mediator for help in reaching an agreement. Or they might have to go to court and have a judge make the decisions for them.
You are not the reason for your parents splitting up. Parents split up because of problems in their relationship.
There are many reasons why parents decide to split up. And with each couple, there might be one main reason, or a whole pile of reasons.
Parents usually try very hard to solve their problems before they take action. If you're not sure what your parents' reasons are for splitting up, you can always ask.
In the vast majority of cases, children get to spend time with both parents. How much time you spend with each parent, and exactly how that will work, depends on your custody and access arrangements.