galeon,
First off, remember that it is your ex's defects of character that are being exposed when they are acting on a resentment (which is usually what gossip is about). The best way I can think of heading it off at the pass is to be honest with everyone about relapsing. Guilt and shame can, and will, kill. The best way to avoid shame is to not keep secrets, they die in the light of day. Use this experience to examine why you relapsed, and change what needs to be changed. The best revenge is to live well! That can only be accomplished clean.

Secondly, you are working the program for yourself I presume. What others may, or may not, think of you is really none of your business. That is what my sponsor pointed out to me. He told me that worrying about how I THINK people are thinking of me is because of another defect of character; it's another type of people pleasing. What I believe they are thinking about me is really nothing but an unproven figment of my imagination, and my imagination is warped by my warped perspective on life. It's really NOT all about me.

Lon

PS:Try praying for your ex- I know it is a bitter pill to swallow, but for me praying for peace for the other person when I feel like I am being done wrong is about all that allows me to move on.