Another welcome from a LGBT family member! I agree with the others--you sound sad but very clear-minded about what is happening to your relationship and to yourself in this painful situation. I think being in a relationship for as many years as you have been (congrats on that!) makes this even harder. I wouldn't be so quick to see yourself as having progressive co-dependence, though it may be, but rather the mere fact that you have loved one person deeply for many years and want him back the way he was before addiction really grabbed him. As a mother, I can tell you I want my AD "back" the way she was before her addictions, but I realized the other day that her addiction has changed who I knew. It doesn't mean I can't love her just as much, I just have to accept who she has become, clean & sober or not. I think this is what we all have to do, and that is where our personal work comes in.
I have found a great community of support here, but in-person NarAnon meetings are essential to your recovery IMHO, and I am sure NYC has plenty. They are for loved ones of illegal substance abusers. The difference from AlAnon is that we have usually experienced extreme situations and lived through huge consequences; we need to be supported and understood differently sometimes because of the legal and extreme troubles our loved ones get into. If you go to one and don't click at first, try another or keep going back a few more times to see who else might appear who is a good fit for you to connect with, kind of like one would have a sponsor in AA.
Here's just one I found:
Times Square | Nar-Anon Family Groups
St. Malachy’s Church
239 West 49th Street
Times Square, NY
Meeting days and time
Tuesday: 6:15PM
I have a therapist, too, but I suggest you get yourself to a NarAnon meeting as soon as you can. It may be all you need at first!
Big hugs, and all the courage you need to do what is best for your health and happiness,
GM