Don't lose any more years of your life with this man. You'll never get them back.
As someone else said, this is addiction and you must treat it as such.
Change his name in your phone - I used the name "Abuser" for mine and you'd be surprised what a big difference it makes when you see it. Even better, block him on all media.
Write a list of all the things you don't like about him, and keep adding to it.
You need to stand up and be the best person to care for yourself, and the best role model for your kids. Just decide to go cold turkey, take it an hour at a time, then you'll be able to take it a day at a time. Pat yourself on the back for each hour then each day.
You'll feel horrible, but that's ok, nothing lasts forever, and then you'll start to feel a little less horrible, then one day you'll realise you felt fine for an hour. And then you'll have a whole day when you felt fine.
You WILL get there and you will also be kicking yourself for having taken so long to start - so get going as soon as possible.