His daughter is and should be a higher priority than his girlfriend. She is his family and you are not. I honestly am not sure why he would even want to stay with someone who has that sort of reaction for something as small as wanting to spend time and a couple of bucks on his kid. My suggestion? Stop being threatened by his daughter. She is his child no matter how old she is and if he wants to spend time and money on her then that is his right as her father. What do you add to that relationship other than drama?