Letting a man move into your house after knowing him for 2 weeks

I’m 18 almost 19 and my cousin is 25 she has two kids a 1 year old and a 6 year old both by different men. I have a baby due in March and she pressured me to move in with her so i could “save money” I did have my own house before. Turns out she just wanted me to live with her so I could be her free babysitter. She has guys in and out her house not a lot but it’s noticeable. I’ve learned that she falls into relationships fast I mean super fast and has about 3 different guys her kids call dad. The most recent one is from out of state she met him on Facebook 2 weeks ago and now he lives with us. She feeds him, buys him stuff, lets him use her car and he even calls her kids out their names and tells them what to do like he their dad. She locks the kids out of her room for hours and leave them with me while they have sex while everyone is still in the house. I’m moving out to be on my own again because I don’t feel comfortable with this guy being around me and I fear for her daughter and son.

Edit: I didn’t mention the way the poor dog looks. He’s literally so sweet and she leaves him in a cage 24/7 literally he sleeps in his own poop and pee. His fur is mated and you can see his bones through his tale and once I shaved him he’s seriously nothing but bones. She hadn’t fed him for two almost 3 months. I bought him a bag of dog food at the beginning of the summer and it’s still full to the stop. So I’ll be taking him and my bully with me when I leave. He’s been getting treated and goes to the vet and eats and goes to the park with my dog. He’s still underweight but doing a lot better.