Whoa! You guys never stop amazing me with how real your world problems are. Makes me feel bad about complaining I only got 5 hours of sleep last night, or that I had a tiny string of apple meat stuck in my teeth after lunch.
My own personal experience tells me that even if this person has changed, Joseph, addiction is a lifetime illness. It's not something you just POOF get rid of. If you have had struggles in the past, you will struggle indefinitely. Does this Joseph seem like they type of person who can handle a downfall and not let it drag him completely? My first very real indication that he would be ready and willing to fall back into his old ways, the moment the backdoor opens, was that he continues to talk to this Michelle. First and foremost, a sign of not wanting to let go of a past, relationship or otherwise, is allowing toxic people or habits to extend their reach into your current life or future prospects. Sure, people have 100 ways to reach out and you can't always stop that initial contact from happening, BUT her unwarranted attacks on your, don't explain the apology he accepted or at the very least conversed about with Michelle.
I really do like how you focused on the point that "he's clean and has a good job now" because that is the second point I wanted to make. People in comfortable situations thrive, but when they are at their worst, and the world has thrown them curveball after curveball, will their character withstand the pressure? I don't know as much about this guys history as you do, but I don't think I would be willing to risk returning to the harassment and stress, for just anyone, who hasn't proved their worth for some time.
Which brings me to my final point. I am not saying that he is bent to fail. I am not saying at all that people can't change their frame of mind or parts of their lifestyle, but I wouldn't jump right back into a friendship with this guy, let a lone a relationship. Personally. I have a 1 year rule. I need someone, from a distance, to prove that they are on this train for the long-haul, for 1 year, before I delve back into a relationship, friendship or otherwise. A LOT can happen in a year, and the chances that he will experience something that will derail him, or at the very least, test his stability, are extremely high. Within that year, you will see his character for who he is now, which you may be surprised is not far off from where he was all that time ago.
Even then, you had to see some redeeming qualities to put up with this guy in the first place, but just be careful. Things are not always what they seem. Trust your mind, not your heart, in most circumstances. Maybe he fits the description of your soulmate, but maybe it's not him exactly, but the person who will finally teach you what your true soulmate actually is. Maybe he's a great person and he really has changed for the better, but the only way to find that out, is to see if he can withstand a year of changes, and a year of waiting to earn your trust back. In my opinion, when you "take a break from someone" you don't just hop over to a new GF and then back to them like it was no big deal. Regardless of circumstances, if you love that person, you wait for them. Seeing as he has shown little strength in that regard previously, that's another trial he would have to pass, if it were me.
All of this being said, you need to really ask yourself if you are ready for the commitment that it takes to be in a relationship with an addict. You need to be honest with him and yourself about what you want, and how much time you think you will need to find trust in such a strained relationship from start to finish. Start the conversation. Don't be afraid to tell him that you need time and distance to just observe his behavior. Don't be afraid to tell him that Michelle can't be part of the picture, not because she's an ex (no confident woman and strong relationship should care about external relationships anyways) but because she seems genuinely dangerous, and that's no good. Test the waters as friends, for long enough to know for sure if it's worth the risk. See what happens, but protect yourself, and think long and hard about your "requirements" in this relationship, and hopefully he'll allow the communication to take place and discuss your concerns. If he spends too much time pressuring you, or making excuses, or talking about how much he's changed without willing the effort to actually SHOW you, then he's probably better left alone.
Thanks for leaving your big life issues to little ol' me!
We'll see ya next week!