First off I want to say congrats on getting off the drugs. That is a great accomplishment not to be taken lightly... now onto the situation at hand. She's married... it doesn't matter why she married or to whom she married, it doesn't matter how she feels about you or how you feel about her, SHE IS MARRIED aka OFF LIMITS. If she chooses to leave her husband than let what may happen happen, but don't hold your breath thinking she is going to do this. I'm not trying to be mean, just honest. Secondly, you say you don't love your current girlfriend? Break it off. She has a child. Do you know how easily children get attached? Do you know how painful it is for them to lose someone and how big an impact it can have on their life? Don't string your girl and her child along. You straight up said you are just with her to be with someone. The longer you stretch the relationship out, the worse people will get hurt in the end. You don't have to love her to have a heart. Step up and be the man. Be honest and walk away. If things between you and the old flame happen later than fine, but wait until she's made the sound decision to divorce and has gone through with it. Good luck with it all. Step back and put yourself in everyone else's shoes. I wouldn't be too proud of the fact that you now have the potential to break a lot of hearts, do the right thing... for you, your girlfriend, her child, and your crush. I think you know what you need to do and I hope that you do the right thing. Good luck in everything and I hope that I've been of at least a little assistance.
<3
Leslie