Boyfriend treats me like dirt?

Been with my boyfriend for over 10 years and we have 2 children together. I met him when i was 15, it wasok at first then he startedto get possessive and would hit me..he would come on to my friends that eventually i had none left. After i had our first kid and got our own place i became reclusive..never went out..i didnt have anyone to talk to so just sat with my baby..then he started going out with friends and meeting other girls and id sit in my pyjamas all day and night crying..wouldnt hear from him for days ...when it was his birthday he spent it with his friends and even stole my kids christmas money..i shouted at him and he repeatable punched me ..after he had gone i grabbed my stuff and got baby ready and walked 7miles to my mums house with our kid in my arms with blood runnin down my face.....hed make fun ofme to his friends and had 1 i didnt know threaten to beat me up..even came down to my mothers shouting abuse whilst i was there..for no reason at all...now ive 2 kids with him and want to leave him...when he touches me he makes my skin crawl..i make excuses to lieon the couch just so i dont have to sleep in the same bed as him...imnot the same as i was before i met him..i was confident and outgoing...now i feel drained ...and bursts out crying if someone says something not nice about me..before i wouldn't have cared now i do..he sits and callsme pathetic, lazy and a waste of space..i never argue back just sit and take it..but now ive had enough and want toleave ..trouble is im terrified i dont know where to begin for this new life i want...ineed help