How do i leave an all around cruel abusive relationship whats wrong w me?

been 2gether 8 yr w 2 sm kids 2gether cheated on 5xs, emot., sprit., ment. depleted havent been any where normal 4 the longest time absolutly despise the person i have become not only is there abuse but i swear he goes out of his way to be xtra cruel, cold hearted and mean. dont believe a word he says, can only depend on him to not be there in anyway, shape or form im totally STUPID for continuously thinking that mayb this time things will chg or get better when i really dont have anything tangible fr him 2 go on. what's wrong w me that i dont walk away fr a totally unhealthy relationship which has completely killed me inside out &cont. 2 eat away @ me. i do know that his claws will always b hooked in me cuz i honestly dont c myself EVER bing able 2 recover fr the hurt, lies, betrayal, etc. ive chgd so much,im now the abused turned abuser. my poor kids suffer so much, dont want my daugt. & sons to b in a relationshp any where near as toxic dont want 2 c hw much more i let him kill me