So frustrated

Within a week Bm's new bf has become my step daughters new dad. BM is married and already has a bf. She didnt even tell us she moved out of her husband's mother's house and is now living with family which my step daughter told me tonight. She also said that she went out with her mom and her new dad. Her mother has a habit of having kids with a guy cheating on them after the kid is born and leaves to be with the new guy. She did this with my bf and cheated with her husband and is now doing it to him. I hate that is the example she is setting for our little girl. She is only 5 and thinks she has 3 dads now. On top of it they told our daughter not to tell anyone about her new bf but she told me. BM had a fit when my bf and i got engaged and said she was not allowed to call me mom. Which i dont care what my step daughter calls me as long as it is appropriate i just find it funny how hypocritical she is. She took away time from us because we dont have a bedroom for daughter but she has a bed a roof over her head and food to eat clothes that actually fit. Now she is with BM sleeping on a mattress on the floor sharing it with her sister in a room with 2 other people. Also her mom doesnt ever seem to have clothes or shoes that fit her they are way to small or she just brings her over with no shoes at all. Im frustrated with her act. I really hope court will end all this bullsh**.