Break ups are hard... I just recently went through a divorce and the emotions you describe are so familiar.. Of course you miss him, that's a natural response but I think you are wise in opening your eyes and seeing the truth.. Missing money, lies etc... Once trust is broken its so hard to get back and I don't ever think we truly give it back to the person that broke it, if that makes sense..
Your BF is coming out of rehab and will be on what is called the pink cloud.. He will seem normal and maybe serious about his recovery.. O course he is because he's been in an environment where no drugs are present and had been able to solely focus on himself.. Rehab is the easy part, dealing with life on life's terms after rehab is the most difficult... The best thing you can do is work on yourself and continue to go to your meetings and still have little to no contact with your ex.. NC is always best but you have to decide what's best for you.. You can be supportive of him from afar without being directly involved with him... Give it a whole year before you make any decisions about your relationship... His actions will show whether he is serious about recovery or not...
Good luck and continue posting here