Well... from what you wrote... I would say your husband is abusing both you & your kids. I'm a guy... well... sort of... it's complicated... (actually an old man.)
But I know what a man's sex drive is all about.
Still... that doesn't excuse the type of behavior you describe.
Plus, hitting your daughter so hard it leaves welts she can't sit / lay on really is over the top, in my opinion.
Yes... he always says he's sorry & probably says it won't happen again. But it always does. That's pretty-much the normal pattern as I understand it. My personal, non-professional opinion is he needs help. But you cannot force him into it. The only thing you can do is to do what you have to do to protect yourself & your children.
Here are links to 3 articles from the PsychCentral archives that may be of some interest & benefit:
https://psychcentral.com/blog/archiv...-relationship/
https://psychcentral.com/quizzes/dom...violence-quiz/
https://blogs.psychcentral.com/pract...-relationship/
Also... are you familiar with the National Domestic Abuse Hotline?
1 (800) 799-7233
The National Domestic Violence Hotline ? The Hotline
I wish you well as you struggle to work your way through this most difficult situation.