Well SouthWest so it was probably sex, you know grannies and grandes.
Seriously, self medicating is almost always alcohol
Easiest as it’s legal.
Still, did the OP pull the plug before he got caught or was HIMS already involved?

This is why you need interview prep next time.
You resigned from your probationary year because your marriage was in shambles and the stress of divorce was too much of a distraction to be able to safely perform your job.

No need to mention SA anywhere in the process unless it’s already ‘official’.
Failed a test or formal therapy or whatever.