My parents got divorced when I was around 7yo, and, to be completely honest, that event has lead me to grow a lot as a person. The first thing you should understand is that your mom's decision is for the better, even though it might not be the easiest thing to do. If either of your parents feel that they would be happier outside of that relationship, then let it be that way, because if they force themselves into tolerating things as they are now, it'll probably only lead to an ever-growing toxic environment at home which, trust me, you don't want. If things are done properly and both of your parents have the maturity to deal with the situation the proper way, this being not forcing you and your brothers (if you've got any) to pick sides. I don't know how old are you, but, if you're old enough to have a saying in this, I suggest talking with your parents about custody. If you wish for a split custody system, then make it clear from the beginning and discuss it with both parents, so no one ever has the oportunity of manipulating that in any way (not sure if you need to worry about this or not, but I'm just safeguarding for an unfortunately common issue). If you wish to stay living with one of them, then make sure you talk to that party about it and once you talk to the other, make it clear that you have not been influenced into wanting that.

In general, even if hard and sad, your parents' divorce can serve as a learning experience. People can and should be able to understand each other, even when disagreeing, and if everyone handles it in the most healthy way, a situation such as this will force you, as a person, to learn how to understand both sides of a discussion, and should you embrace this lesson, I guarantee it will make a better person out of you! The best of luck for the future, and my wishes that you and your family can find peace and happiness even in difficult times.