Verbal abuse not only affects yourself, but your kids as well and their overall development. It may not be obvious now or they may not speak up about it, but each fight and each mean word said will stay with them for awhile, if not for life at that young of age. I'm sure they see their mother being treated badly by their father and eventually they internalize that and may start blaming themselves. If you can't leave the relationship now because you're hoping he'll change, then at least try to help your children out in some way. I think if you allow your kids to stay in this destructive and dangerous environment, then at least have them see a therapist. Everything a child goes through now, builds them into what they'll become in the future. Negative or positive. Help them if you can't find it in yourself to leave just yet.
Like another person added, sometimes heading into the unknown can be terrifying when all you've ever known is the life you've had for the past few years. It's hard knowing you have to leave behind that sort of comfort, but if you take that leap, I promise you won't regret it and I promise you you're much stronger than you think. It may be rocky at first, but just trust that you've made the right decision for yourself and your kids to leave.
You ARE strong and you must realize YOU matter! You just had a major surgery for yourself making YOU a priority! This is the first step. Make yourself and your kids your priority. When your husband accuses you of cheating and looking too sexy because you've lost weight, it's just his attempt to manipulate and control you. Any time you feel good about yourself, he fears you will leave, and he plants things in your mind like "you're not good enough. You can't make it without me. No one else will love you" and things like that. Eventually tou start to believe it. That's why it's so hard to leave right now! See what he's done? He played this mind game with you, your self esteem has faltered, and that's just what he wants! He's a coward, that's all. He's insecure himself, and needs to beat on you emotionally so he can control you enough so you'll say to yourself "He's right. I'm not good enough. I need him. I can't make it on my own" so you just keep staying. It's a cycle only you can break.
Hang in there Mami. It's hard to find the courage to leave, but you have it in you, you just need to look deeper