There can be many reasons for not leaving an abusive partner.
You want your children to have a father
You don't want to lose your home
You don't want your children to change schools
You can't support yourself and your children
You're undocumented and you don't want to risk being deported
You don't want to shame yourself, your partner, or family
You're afraid of being alone
You love your partner -- and other reasons only you know
You are afraid to lose custody of your children
It is against your religious beliefs
All of these are real considerations. You are the only one who knows how dangerous the abuse against you is. You are the only one who can judge when the pain or danger is too much and outweighs your reasons for staying.
When thinking about staying or leaving, ask yourself:
Are my reasons for staying so important that it's worth it to stay and take the risk of being beaten or killed?
Am I less likely to be hurt or killed if I stay, or if I leave?
What is the abuse doing to my children and their future relationships?
Where and what do I want to be in five years?
What course of action is most likely to get me there?
You might not like any of the choices you have, but you do have choices. If you have thought about what is most important to you, you are more likely to choose well in a crisis.