Pregnant and dealing with partners lies

im not married, but my partner and I have been together for just over 3 years. I am 20 and he is 22. We have been living together for a year and we are expecting our first child in October. He was diagnosed with ADHD very early in life and was on medication for it until high school, but is no longer on it. I'm struggling to find a way to deal with and put an end to his pattern of lying. He has never cheated on me (that I know or) but he will lie about EVERYTHING, even if there is no reason to lie. Sometimes it's flat out lying to my face, other times it's lying by omission. The current issue in dealing with is him lying about what he does when he hangs out with his friends. I can sometimes be controlling because I struggle with anxiety as well as a host of other mental health issues, but I very rarely ask him not to hang out with someone, or go do something he wants to do. I hope that after we have the child he will stop spending the night at his best friends house but I don't have a problem with him doing it now. However, 


He knows that I don't want him smoking weed. It's just something that I need out of my partner, and I don't really know why, I just don't want it in my life. Granted, I don't care if other people do it, I'm not one to judge, I used to smoke it myself, but I experienced severe psychosis when smoking it and haven't done it since. He does not use it for medical purposes (he's told me himself it makes him feel slow and dumb) yet I found out yesterday that he has been smoking it when I'm not around. I don't really think it is the fact that he was smoking that bothers me the most, I don't like it, but it isn't what gets me upset. Him hiding it from me and lying about it to me when we would talk about what he does with his friends makes me upset. He refuses to have his friend over at our place ever. He hangs out with his friend more than he hangs out with me so I've asked him several times if they could hang out here more and he says no. Now I know why. He told me that his best friend and him have only smoked it a few times together. He also promised that he wouldn't smoke it anymore because he respects my wishes. Yes, my trust in him is lacking so tonight after he fell asleep I looked at his texts messages and his friend was making me out to be the bad guy because I asked him to spend some of the day with me instead of spending it all with him (I said he could go over there after dinner, not like I said they couldn't hang out). His friend asked him if they were still going to get stoned and my boyfriend said not this time. When I read that I got sick to my stomach. He basically told his friend that they can't do it this time but whenever he can get home before me and shower or spend the night at his friends they can do it because I won't find out. He doesn't respond my needs and wishes. We have had several conversations about what I need from him in our relationship but he never does anything differently. He avoids any important conversation. I am going to confront him tomorrow when he gets home from work and we are going to have a very serious conversation. 


I think part of the reason it makes me so upset that he doesn't show me the respect I want is because this entire past year we have lived on our own, I have paid all our bills by myself and he never seems to have any money to help out, even though he makes as much as I do each month, because he "doesn't know where his money is going". I just feel like he is hiding so much from me and it is very hurtful and hard to deal with. I'm honestly at the point that if we weren't expecting a baby I would tell him I can't do this anymore and leave. I would pay the bills so that my rental history isn't shot but after our lease is up that would be it. Also, I bought him a car a year ago. I bought it from my dad who sold it to me for a good price under the conditions that when the title got switched over it would be in my name. I found out last week that he went and put it in his name so if something did happen I wouldn't get the car that I paid for. I just am not sure what to do anymore. I love him, but I'm so tired of being lied to. Any advice? He doesn't want to be on meds. He's very stubborn and doesn't think he needs therapy. I just feel very alone and stuck. Any help is appreciated.