3 year old going on 13!

RA

I’ve had enough of my 3 year olds attitude. Her dad and I split up almost a year ago. I moved on and am currently in a new relationship. My bf loves her and she loves him. But the past month everything is an argument. “Eat ur dinner” NO! “Go play” NO! “Play with your tablet” NO! Alllll day from the second she gets up to when she goes to bed this is what she does. Or she tells us to leave her alone. Now. Her dad claims she doesn’t do that with him. But part of the reason we split was his lack of parenting. He doesn’t hold her accountable for anything. If she breaks something on purpose he laughs. He lets her throw her trash on the floor and not pick it up. He doesn’t pick it up. He lets her do whatever she wants. I’m 17w pregnant and so stressed because I feel like my 3 year old has control over everything no matter how hard we try. Between time outs, taking things away, tapping her butt (if u have anything beg to say go away), ect. I really don’t know what to do.