Abusive new stepdad?

Let’s get to it, Saturday was my 23rd birthday. I don’t have much, I don’t have millions of friends to shout congrats to me. I have my mom and my fiance and a puppy. That’s what I have.
This Friday from 2ish to 7. Me and my mom were out, we ate sushi, we brought some snacks to watch a movie together at home. Sang in the car. It was nice.
At 8 she leaves, she leaves to go visit her new boyfriend, go to his place. I didn’t approve of that because in a few hours I turn 23 and I wanted her there. But she left, anyhow…

I woke up by noon, mom wasn’t home. I figured she’d come home in a few hours to be with us and watch a movie we were going to see. Time passed and I got more and more annoyed, wasn’t before 7 in the evening when I got angry, I felt sad, betrayed. She was busy being with her new boyfriend, not even been together a week. My fiance made it up to me a few min pass eight with some snacks, a few drinks and.. It was ok.

A few min pass twelve I get a phone call to hear that my mom is very sad and upset. They were on their way home and she sat down tears in her eyes, she was scared. Because this guy had put his hands on her, he’d pushed her, hit her shoulder, called her name and threatened her. That if he was in pain the next day, he’d beat her.

Anyhow, we both agreed it’s over and he’d been immature to block her everywhere, said bye and all that. Just being a general fucker.

She earlier the Sunday around noon came to my room and said she was going to go meet a friend and once more.. She was gone all day and night. I got a message at nine with her saying “Me and [guys name]’s been talking and I’m the one overreacting, it’s a huge misunderstanding.” And loads else, I gave a simple respond “No.” I wasn’t going to have that, told her to come home and she was brining him here and I once more said; No. So she said she’d come alone to talk to me. We did talk, but it was just her trying to justify it all. “He had mixed drinks, he was drunk..” And tried to put the blame how he treated her on her sister. I told her she was dumb, I was done with her bullshit. FOR LYING TO ME, after everything I do for her. And appearently two of her friends for her going to him turns their backs on her, TWO FRIENDS WHO ACTUALLY DID SOMETHING GOOD AND SUPPORTED, HELPED. Along with her trying to blame her sister and shitting on me, her daughter.
2 friends, her sister, me < Abusive asshole.

I am beyond pissed.