Unhappy life

For some reason I can't ever feel satisfied with my life. Everything gets me down and very few things can make me in a better mood(although I usually hide that I'm not happy). I feel like I had my son too early even though I was 20 years old and I love him more than anything in the world. I could never leave him and I always try and do best for him and take care of his needs first. Anyways I grew up pretty poor in my small family and didn't get to experience anything and now that I have my son I feel like a lot of options are out the window and I know it's not my son's fault and I can still do things while raising him but I never got the chance to get my life together before I had him and now it's harder. Every time things start to slightly go better for me something terrible happens and I have to go 2 steps back. My boyfriend/child's father is 10 years older than me but has done nothing with his life. I think I almost resent him for the things he has done when we have split up twice in the past 6 years. He pretty much abandoned us and didn't want anything to do with his son unless we were together because he was always preoccupied with drugs and other women that were even younger than me. And when we got back together the first time, he had slept with a girl that tried to be my friend and was a known easy slut of this small town and he claims he tried to get back at me and make me mad cuz I didn't want to be with him and his drinking anymore. Anyways he came back and I contracted a disease from him because of this girl that I have to live with for the rest of my life. Now I feel like I'm stuck with him because I don't want to pass this along and make someone suffer like I did so I stay with him. But I think that I want to be with him, I know I love him but it's sometimes too hard to get over and let go what he has done to me and my son. He has lied to me more times than I could ever count, about drugs, drinking and now girls even though we weren't together. I just can't trust him even though he says he's tired of lying all his life and he wants to tell the truth but I don't know if I can still trust him. I find out new information about more lies and sometimes he gets mad and says it not true and other times he comes out and tells the truth. I just can't handle all the lies on top of all the stress I already have to deal with. And he just thinks that I need to forget about it all and get over the past which I know there's nothing I can do to change the past but it keeps repeating itself in different forms and I can't get over how much I've been hurt and finding out all the lies and not knowing that just because I haven't found the truth then he doesn't have to tell me the truth and can continue with all the lies. I do want to get over it all and have a happy life with the family but not when nothing has changed and I'm so unhappy with everything.