Abortion

My EX and I broke up a week before I found out I was pregnant (5weeks). He wants me to get an abortion but I don't want to... He says that I lied to him because I told him I didn't want to have kids at this point in my life. I did say that but things changed when I found out I was pregnant. I don't know how to explain to him what I am going through. I want him to be there for the baby but he resents me because I am "ruining his life" and he is actively trying to get me to change my mind. I feel horrible... He makes me question myself all the time. Any advice?