20 years ago, I could have written this post.
OP, let me give you some advice from experience. Both mine, and my DD's. Her biological father was very abusive, to the point that when I left him - not knowing that I was pregnant - I did so in genuine fear of my life. He also trashed his parents house... and blamed me. Even though I wasn't there when he did this, it was because of me apparently 
I found out that I was pregnant a month after I left him. My mother decided to inform him/his parents... and then had a barrage of phone calls from him dictating that I had to get an abortion, he wasn't paying for the child in any way, shape or form, blaming me for ruining his life. His parents, meanwhile, simply dictated that I wasn't allowed to get an abortion because they were Catholic (bully for them... I'm not!) and that their precious first born was just a child (he was 20) and didn't know what he'd ever done to have me ruin his life...
I had the baby. My DD. She has never - to the best of my knowledge - met her biological father. He certainly wasn't allowed anywhere near me during my pregnancy or immediately after it (my older brother stepped in and forbade it). And he's never paid a penny towards her. I raised her by myself. She had a relationship with her paternal grandparents (my mother insisted on them turning up to "meet" her when I was 14 hours post-labour and reeling with the shock still) until she was 7 years old, at which point... she simply refused to see them. Turns out that she was being sexually abused by her grandfather, whilst her grandmother was telling her that she was never going to see me again. This has only just come out in the last few weeks... but would explain a lot of her behavioural problems over the years.
Whether you choose to keep your baby, or not... it is your choice. Not theirs. Not his. Not your parents. Yours. He doesn't need to be at scans, or there when you meet the midwife. He has told you who he is. Listen to that. Learn from it.
Because as PPs have said... both you and the growing life inside of you deserve better than your ex will ever be able to provide. For either of you.
I didn't think that I could ever be a single mother. But I have a wonderful, smart, beautiful 20 year old daughter who is currently sat upstairs working on an essay for her university course and a 12 year old at school... which proves that I could. I did. I am.
Take control of your life, OP. Don't let your ex dictate to you. Don't let your parents or his do likewise.
You are worth more, baby or no baby.