Im scared to be a Mommy...

So, I watched my Mom mess up with me.... & Ik I won't be like her bc I've learned from her mistakes. But I still get the feeling that I might fail as a Mom.... I'm about to be 20 weeks. & I'm scared as hell. This is my first pregnancy, & the father purposely knocked me up, then left saying some bs "it's not mine". I told him I'd get a DNA test when the baby is born, so he better be at the hospital when he or she is born. The other day we had a conversation.... He doesn't want a DNA test now. Bc he wants to see if it'll look like him. Obviously it will bc he's got black hair & blue eyes. I have red hair & blue eyes. Black is a dominant trait over red. & Blue is a recessive trait for eyes. He or she will be beautiful. He says he doesn't want a broken family... But he was the one who did this.... He cheated on his new girlfriend with me throughout my whole pregnancy so far since he left me for her... & Idk how to feel. I'm scared bc I don't want to be like my Mom. & I'm emotionally confused & unstable bc of him... Do any of you guys have any advice....? I could really use it....

I have tried moving on from him. But he always ends up right back where he wants to be, in my life. After he told me to get out of it & stay out bc I showed his girlfriend messages & pictures of him with me while they were together. She's still with him. So I think she likes to get cheated on. Bc that wasn't the first time I showed her those things..... Or she's just a little slow & thinks he's gunna change for her... When in reality, he won't. I was the only one he changed for bc he broke his phone when we got together & I lived with him, so he couldn't cheat or anything. But I really do need advice from someone older than me.... Bc I'm honestly not ready for this 18+ years with him... But I'm so ready to see my baby..... But I'm scared I'll screw it up... I am only 18... I got pregnant a month after my birthday...