Should I just leave and give up

I’ve been married to my husband 5 years and we’ve had our ups and downs .. lately he’s been struggling with a drug problem and he just confessed to that that when we was at his friends doing his drugs he asked for a his friends sisters number .. he said he never texted her since he has no phone due to him breaking it two weeks ago .. but to me i still feel he betrayed me .. we have a 4 year old and I’m expecting our second child .. he hasn’t been home all day and i just feel very tired and Extremely worthless .. I never wanted to have a second child because of how our relationship was but when I thought we were finally past all this I decided I wanted to give him what he wanted which was another child ... I just feel so stupid because it’s like I just allow him to do these things ... and me being pregnant just hurts more than the other times