My DOC is any type of pill opiate and like you have been on the roller coaster for 20 yrs. I am 57 now. Longest I have stayed off was 9 months about 7 yrs ago and 6 months in mid-2008. I am now clean 5 months. It will always been one day at a time for me, although some days I don't even really think about using now or really miss it, but in all honesty if I had a bottle now I probably would be tempted. I always missed it before, especially when my Alcoholic spouse was drinking (he has been sober 5 yrs now). I am so blessed to still have a family, job, no legal issues, home, good friends, church family, etc. I have to work on my codie issues though as that is what led me to using initially and is a trigger for me - mainly trying to control others whose behavior is out of control . . and that leads me to fear, embarassment, emotional pain. I try to be perfect and be all things to all people.
Discovering that fact through SR friends this time around and just hearing similar stories to mine and reading and posting here has really made this recovery unique to me. Most of us have experience multiple relapses, but keep trying. You have been clean 3 years before which is great and 1 year up until a few days ago. You can do it again! Keep posting and you will find a lot of support here.