Girl, sharing or not is all up to you. For some people it can help to get it of their chest - even more so if they can do it to people they won't see at work next day or at the next party. They should share.. Then there are those that prefer to keep it to themselves. They still can share, but should feel compelled to do.
Don't know the specifics of your situation, but indeed your mom was brave to leave your father, for that action you should be proud of her.
You were a kid when this happened, so you are not to blame. Never.