Sometimes, for me atleast, I tell myself those things to get myself through a difficult moment. When I start to question my decision in asking him to leave I replay it over and over and always end up with the same conclusion I couldnt live like that.
I really think my ex was angry that I asked him to leave and thought "screw her, I will show her that I dont need her and that I can make it on my own" hence the MY LIFE IS GREAT statements I got. But then reality starts to set in and they realize they really arent happy and that it wasnt you it was them. The same journey we travel when we realize it wasnt us it was them.
I truly believe that if the relationship was great before drugs/alcohol then that was the problem. When they figure it out they at the very least will come back to let you know that. They would have to in order to make amends.
I also learned to stop expecting things. If I expected him to feel a certain way and he didnt I was crushed. I expected him to be better after a week in rehab. He isnt. I was crushed. Now moving forward if I stop expecting anything other then what I have been getting with him its easier for me. If he changes I will be SURPRISED. If he doesnt change I will ACCEPT it.