A lot of the time, the night vanishings would have not been something I noticed. She'd wait until I was asleep and be back before I awoke. Whenever I did notice, there was an excuse 'Mate's dog went missing' 'So and so needed some help with X' 'Couldn't sleep so went for a walk'. I just believed her.
She worked, as I've said in the OP, there was usually a 'legit' albeit low-level job alongside other earning means.
I actually met her at work, she was on the door and behind the bar of a dodgy club. I was studying in a neighbouring city and got a part-time job promoting for them. Other than that she did other bar work, gardening, other odd jobs.
Money was always to an 'easy come easy go' attitude with her which, now I am a bit wiser, seems to be normal for these sorts of circles. Whenever she took me out, or bought me things she'd say things like 'Make the most of this, once It's gone It's gone!' I guess if you're involved in dodgy practices, you cannot be seen to be making money, so it has to be spent, it cannot be invested or used for larger material things.
I agree she was/is damaged. I think I perhaps was too, despite a relatively privileged upbringing. But I was naive, having never known these sorts of circles existed or at least certainly not in a world that would overlap with mine.
We got friendly with one another while I worked at the club. She'd always offer to walk me to my car at the end of the night, which was appreciated. One night, I gave her a hug goodbye and I have never felt chemistry like it before or since. Please don't think I am a hopeless, whimsical romantic, I am far from it, but I remember that moment as very strange, in a good way. I just could not let go of her. Also relevant perhaps is that, as a young gay female I was in total denial. My family were an issue, and I had had relations with women but not real relationships, up to this point. So it being my first 'real' lesbian relationship likely played a significant part in why we got together, and why I stayed as long as I did.