Relationship advice..im going crazy?

this is a situation i never thought i would find myself in. so here it goes..i have been dating a man for the last 3 years. i guess its time to admitt that it was a pretty bad relationship. we fought all the time, but still couldnt break away from eachother. i guess some people have called him mentally/emotionally abusive...i dont know, i never thought of it that way. anyways it took three years for me to break free from him and every day since then i have missed him. he was my best friend and i got so attached. its been 4 months since weve been broken up and ive met someone else. this someone else is the absolute most perfect example of everything any women could ask for. he was rasied right, and knows how to be respectful and sweet. hes the complete opposite of my ex. im so happy and feel so good about him, but hes not the one i love. now 4 months later my ex of 3 years says he cant be without me and he loves me and needs me back. and i know he loves me. he says he can change and things will be perfect. this is so difficult because yes i love him, but how do i know he will change? and if he doesnt im giving up something amazing. this would be the millionth time weve broken up and everytime we get back together its great for a month and then turns to ****. but im in love and want to believe him. im so confused. any advice would be greatly appreciated. Relationship advice..im going crazy?
Stop going back, dedicate yourself to only going forward. You know in your heart it won't work with the ex. Focus on the great guy that you have.