Venting

I have been with my boyfriend for 3 years I have a son who is now 6 with my and he has a daughter 4 with his ex and about a year ago he finally got visitation and in the beginning he always said he would treat my son and his daughter the same since he says my son is his son (my sons father comes and goes when he pleases) but ever since he got visitation its been nothing but arguments after a while because what he doesn't want my son to do and gets mad he led his daughter do n I tell him n he gets mad telling me to mind my business he gets his daughter every month for 2 weeks he says that mother doesn't discipline his daughter she just wants to be her friend but he doesn't discipline her either and whenever she doesn't get her way she crys and gets exactly what she wants so there is no parenting on either side but when my son use to cry when he was little and he got way he wanted my boyfriend would be furious and he keeps using the excuse that my sons a boy and his daughter is a girl basically my son can ask him something and he would scream at him and tell him no in a firm voice but when his daughter asks the same thing a few seconds later he would say no baby in the softest voice ever which isn't fair and on top of that when she comes I'm invisible it's like I don't exist am I over reacting?? I tried talking to him about it about an hour ago and he said he doesn't care what I have to say and he doesn't wanna hear it he just thinks I hate his daughter