AITA for moving out?

Other than college I have lived with my parents. My dad died and she has his insurance money and retirement to live off of.

I have a 2-3 hour commute to this job I got last year. It’s draining. On top of that my sister had a baby about a year ago old and I am repeatedly asked either by my mom or her to pick up things like diapers or food for the family on my way home. My sister works a retail job right by our home but for some reason me picking up things for a child that’s not mine has been falling on me and my sister or mom never pay me back.

I met a woman at my job so I have known her a year. We’ve have dated for 6 months and I have stayed at her place in the city almost 2-3 nights a week now. It’s 5 minutes from my work. She told me her lease is up at the end of September and since I stay with her so often we decided to get an apartment in the city together and found one about 3 minutes from my job I could walk or bike if I wanted and no more 3 hours commute on a Friday night.

I told my mom and sister I’m moving out. My sister flips out on me saying how can I do this to her and she can barely afford taking care of mom and the baby. I told her mom has dad’s death benefits and mom gives her money so it’s the other way around mom takes care of you and the baby. Then I’m expected to take care of everyone else. My sister started crying calling me selfish and she doesn’t know how she will do this. I told her I’m not your baby daddy and if you are having such financial problems you need to get children support. She told me that she doesn’t what the father in her life. I told her that maybe she should have thought about that before she f.cked him. I told her that’s this situation is all yours and his fault.

My sister threw a fit yelling and screaming at me. My mom said I was wrong and I need to apologize and I need to make a plan for the bills going forward. My mom acts like I should still be financially supporting them when I move and I said no. My mom acts like I shouldn’t move into this apartment with a woman I have been dating for only six months and I asked her why can my sister have a whole child with a man she hardly knew and no one says shit to her?

My mom became angry with me and I packed some of my shit and the more expensive things like the tv, computer and X Box and asked a friend to move them right now. I stayed with him that night and am moving in with my girlfriend ASAP now because of my mom and sister. My mom and family acts like I’m the bad guy for how I spoke to my widow mother and my single mom sister because they spin the story that they can’t afford everyday things without me.