my baby father lives with me so of course he be around my son all the time but no matter what I…

my baby father lives with me so of course he be around my son all the time but no matter what I feels doe he should be giving me more money for my son then what is I shouldn't have to argue just to get money from him and bad enough I don't have that much money and I got to get my girls stuff cause there dad's not around like I'm really getting fed up I don't know what to do