I hope he pays child support. Other than that you have no control who he is dating or living with. Please do file for child support if you haven't yet

But I recommend to either stop sex with him or at least use protection. He sleeps with more than one woman and it's dangerous (std). He sounds very trashy and most certainly he isn't the type to have "family" with. File for formal custody agreement and child support but it might be wise to stop sleeping with him