Thanks for your reply, trailmix.
I did read Codependent No More this past summer during the second separation and found it incredibly helpful. It definitely helped me to realize a few things inside of myself.
In response to the questions asked, I definitely do deserve a stable and consistent relationship full of love and happiness. I don't want to date someone that is a meth addict and cheats on me. The thing is that I was under the impression that things were getting better and he has been changing. I can tell you it's a different person from December and even July. If he was not working on himself, I would not even try. I would have ran away. But because there is love that seems mutual and that he is working on himself, as am I, that's why I chose to enter the relationship again.