So, first things first. What is your actual experience in casting spells or doing magic of any sort? You must understand that you can't simply find some words on an internet site, say those words, and maybe burn a candle or two and expect any thing magical to happen. Magic is a bit more complicated than that and requires some study and practice before it likely your spell will work.
In addition, I am a great believer in combining any magical action with a mundane one. If you don't have a getaway bag you should think about packing up those things you would most need if you have to run. Think about your identification papers, some money, a change of clothes, and some basic toiletries. Put them all together in a bag of some kind you can grab quickly and run. If you have your own car, think about keeping them in the trunk of the car and make sure to have an extra set of keys you can get to if he takes your usual set.
Identify a safe place to run to if you do have to leave in a hurry. Do not go to a friend's house! That is the first place he will look and he might harm your friend. Most towns have women's shelters which are places for protection of women fleeing abusive relationships. Find their phone numbers and keep those with your getaway bag. These shelters generally do not list their address, so you'll need to call them to find out where they are.
If you do need to look into magic to help your situation I would recommend that you look at a protection spell for you and your children (if you have any). You're not likely to be able to banish him from his home. But you can work a protection to keep you safe when you leave him. The Shop here on this site has a Protection Kit complete with instructions that might be what you could need. https://www.spellsofmagic.com/shop_details.html?c=R&s=Sp...
What is it you expect to accomplish with a banishing spell? What time frame are you hoping to have this work in? What things are you doing now based on the advice you have already received?
I definitely understanding wanting him gone, but sometimes the best option is to be the one to leave. I don't know any methods to control another person. But I do know it's possible to make your own choices, even when they're so extremely difficult.
