Spiritual joy is a difficult idea to communicate but, as an exuberant sexaholic, I shall try my best.
The AA Twelve Steps and Twelve Traditions talks about the "joy of living" (p 106) and our SA book Recovery Continues has an entire essay on The Joy Response. I believe spiritual joy has a lot to do with the "crucial change in attitude" that is described in the White Book reading The Solution.
Before recovery I had progressed to the point of NO JOY. I had momentary material pleasures from drinking, drugging, acting out and playing video games. Negative attitudes and emotions also gave me a twisted sort of pleasure.
I used to wake up with the attitude that people could not be trusted. I was on hyper vigilant watch to make sure that no one would get the best of me. I had the beliefs that my wife was unlovable and God allowed terrible things to happen to people. I had no desire to be in relationship with anyone, not even my acting out partners. I hated my job and my coworkers. I was basically just living out my life waiting to die. It was all Terror, Bewilderment, Frustration, Despair (AABB 151).
Now I am absolutely full of joy. I wake up today and I put on an attitude of joy. My morning prayer is "God I can't wait to see what you have in store for today! How can I be of service to you?" I am not living in some sort of superficial fantasy world. Today, I am living in spiritual reality - that we live in a world of absolute abundance. I can honestly say there is no acting out scenario that would be better than the joy I experience today as a recovering person. I humbly admit this new attitude is based on the daily maintenance of a spiritual condition.
Maybe this passage from the Big Book expresses the spiritual joy best:
"Like a gaunt prospector, belt drawn in over the last ounce of food, our pick struck gold. Joy at our release from a lifetime of frustration knew no bounds. Father feels he has struck something better than gold. For a time he may try to hug the new treasure to himself. He may not see at once that he has barely scratched a limitless lode which will pay dividends only if he mines it for the rest of his life and insists on giving away the entire product." (AABB 128-129)