So your faux pas happened in the beginning of that sad story. Instead of apologizing, you needed to tell her that your privacy rights were important. In other words, no snooping.

She is free riding on you. She does not contribute to the household financially and she wastes her time seeing the addiction therapist. She should be using whatever waking hours she has in some sort of productive fashion, in order to get out of the depression and actually do something positive, be it get a job or at least stop making you miserable.

Exercise, sunlight, etc are some of the ways to treat deepression in addition to or instead of psychopharmacology.

SA meeting attendance is unlikely to treat her depression. So she is wasting her waking hours.

Sex addiction is poorly defined and the sites you visited lack scientific rigor, but since you do not meet even their definition, it is crystal clear that you would never meet any conceivable definition of sex addiction.

I do not think that arguing with her supporters would help because you are trying. To defend yourself from the position of logic and reason and they cannot care less about that position. You won't win the argument. It will be another faux pas, similar to the one you made in the very beginning.

Try to shift the focus, tell her to get a job. Be a little firm, if you can. You probably cannot... you sound very kind-hearted.