why why why and how???

I’ve send a topic in before about me, my child and his father, I realy don’t know any more and I can’t seem to realy talk to my mother since she is one of those people trying to see only the best in others. Well, we are back together, me and my baby’s father but he just goes on like what ever I say or do doesn’t matter, I want to take things slowly and carefull. Because our past is not one of the best ones that I’ve heard of before.. He called me a %%&^$ he said the baby isn’t his, did not want to help at all with anything. till NJ our son turned 9months,.The problem now: he doesn’t ask me about the plans he makes he’ll just walk into the house and tells me about 9 at night "o, I am sleeping over tonight" He will help me with NJ but not really, if he is bussy with friends I just have to keep on running around like a mad chicken for him and my son. Like this weekend he was in the tv room with a friend and Nj crawlwd right past them out the door to the SWIMMING’Pool when I asked him he said the dogs is looking after him…the dogs wasn’t near by and it is not a dog’s job to look after him it is his job. All the rules I make in MY house he tries to change…..
Yes I’ve spoken to him 3 times about this but everytime he does the same thing. I just feel I’ve brought NJ into this world by myself, been alone with NJ till he turned 9 months….