Rant about partner

So I'm probably over reacting but I'm seriously so stressed out. Gets 3:05am and I haven't heard from my partner since 9:30pm. Every weekend it is the same shit, he goes out drinking probably doing drugs too and I'm just left in the dark until he decided to return home either 5 in the morning or sometime the next day. I have spoken to him so many times about it and he says he is gonna change and that the next weekend he doesn't have his kids that it will change. Well no it doesn't and I have less then 2 weeks left and he still goes out lets his phone run dead. And not to mention when he is at home that's all he does is sit on his phone. Constantly! What if something were to happen with me? Labour wise? That sounds a bit selfish in writing. But you get it. Anyway, he always starts arguments with me and says you just want your old life back, drinking and partying. You don't want to be a family person so I'll just take the baby and you can do whatever. Um excuse me!!! Firstly not once have I said that! And secondly who is the one that every weekend and usually 3 days during the week goes out drinking and 'partying' you sir! Not me!! I seriously don't know what to do! I love him so much but I'm really getting fed up with it.  Sorry I really just needed to rant and get any opinions good or bad.