14 weeks pregnant

So I'm 14 weeks pregnant and have just found out that my partner has been messaging other chick's amd asking for their snaps and nudes. He said it's because i pissed him off. We have been fighting as he doesnt want to ease up or quit smoking weed. He smokes from the minute he wakes up to the minute he goes to bed. Which is sometimes 2-3am. He will come to all my midwife and ultrasound appointments stoned. We live together currently at my grandparents. Hes spending roughly $400+ a week on it. And doesn't want to help save for when bub arrives. This will be both our first child. I've had trouble conceiving. So I see this baby as a blessing. But he says he doesnt need to grow up.. and that im the only one that does. Im 22 and he's 29... I try to bring up our problems in the relationship but he sits there quiet on his phone and just ignores me. I'm at a loss and just dont know what to do...