anyone explain why he was like this to me?

ik its been 4yrs now, but i was still young and naive at that time, i just started my life, and had no one to talk to. thruout my life, my parents were really strict and overprotective of me that i never get to go out as much. anyways, here goes.., so i met my bf, now husband, at the age of 18. he was 25. my parents were against us dating, due to him being a divorced, and engaged once. he was my 1st bf ever. i still dated him, regardless. we were on and off. 3 mths into our relationship, my parents has had it, and took my phone and laptop from me. not allowing me to go to my martial art class. they made me choose him or my dreams, which was martial arts. and they read all our messages. which i was embarassed cause we were sexting, so i ran away. i ask most of my friends if i could stay over for a while. but none of them would let me, so i had no choice, but to go to my bf. he knew about it cause my sis ask him if he knows where i am. so i stayed w him for 4 days. he ask me if i want to go back and i say no. so he wanted us to never look back, run away, and slowly build up. my fam eventually found me and forced marriage upon us. he wasnt happy about it at all, he almost drove and ran away, but couldnt cause they were blocking him. so both families worked on a wedding ceremony, i had to stay w him while they were doing it. he began abusing me after i moved in w him and his fam. he would just drink 2 cans of beer, and lied about getting drunk. he would abuse me, pick me up and throw me around. he would compare me to his ex wife that shes best cause she could make him feel better when hes mad. he tells me i dont complete him, theres a missing piece. and that hes only marrying me because he had to, not because of love. he promised me he will cheat on me. i was pregnant, intentionally, after a few days of moving in with him. he would drink and say that he wishes our baby dies instead of his ex fiances baby. he wishes his exdiances baby lived instead of mine. because he doesnt believe my baby is his. hed hit my stomach lightly. and when i run away, hed act all innocent, all sorry, and lured me back in. but once i got in, the abuse starts again. he tells me he will turn our kids against me and only tell them about his ex wife. this happened the day before our wedding. after our wedding, the abuse started again because they were drinking. hed tell me hes going to cheat on me and he even checked out a woman and my cousin, up and down, during the wedding, because he accused me of checking out my brothers guy friends. 4yrs now, hes changed a bit, after many separation. but his abuse hasnt changed, even tho it has lessen. im now 23, gained a bit knowledge about life, i cant believe i would put up w that, and didnt understand why i just didnt leave. i also dont understand why he was treating me that way before during and after our wedding. he told me that if my family never found me, he wouldve never shown his abusive side to me.