Should I trust again after so much??

We met in July, we've been together for little over six months now but I KNOW I'm in love with this man.... We met once before (before this time) he was working at a bakery and I went in, I'm anti-social and I literally CAN'T talk to anyone, but somehow I ended up talking to him for a couple of hours.... Anyways, I found out the second we met that he has a daughter and an ex of course.... We decided to move in together and things were good at first and then he started to screw up.... He started smoking spice. I don't know if anyone knows what that is but it is the WORST drug I have ever had the displeasure of knowing.... He and his friend decided it would be fun to lie to me and smoke it behind my back, the first time I caught him was on my birthday.... He told me he wasn't feeling good so I went to the store to buy him soup and Gatorade and what not just to come home to find him higher than a kite.... We talked about it and it took another month before I snapped. I trusted him one more time with his "friend" and I found them high on the side of the road. I made him walk to his parents house (right around the corner) and I went home to cry myself to sleep. I finally got him to agree with me that he NEEDED to stop so I stuck to his side like glue for a month as he went through withdrawals.... After that things got better again.... But then he started hiding his phone.... Which made me suspicious. So one night I checked his phone (I fought with myself for a week over this) and found text messages from his ex. I questioned him and he said he didn't know who the number belonged to, so I used face book to figure it out. It was her. Why would he lie? So I asked and he said he wasn't so I trusted him again. I asked him when was the last time he talked to her he said months, but when I looked at his phone he talked to her on the 20th. He says his sister gave her his number but HE CALLED HER FIRST. I know he's lying but he refuses to talk about it, he accuses me of not trusting him and gets angry and leave when I try to talk to him about it.... I understand that he HAS to talk to her because they have a child together but why can't he tell me that he is? Why does he hide if from me? He proposed but I don't know if he's trying to cover up for something or if he really does want to get married. The last time we talked about him talking to her he said he would talk when he's ready to. But what about my feeling and concerns? What if I need to talk right now? I really love this man with all my heart and I don't want it to end. Someone help me please????