Hey Roobyroo,
That's so sweet, in weird circumstances!
I would suggest that probably not be so honest to begin with. (I'm too honest with people and it can backfire!) There is no reason to tell him and open up that can of worms, when you don't know him and are leaving the industry anyway.
I know what it feels like to want honesty from the outset, but if you really like him, it's probably best not to burden him with 'the baggage' his brain will feel trying to deal with it, or letting someone you don't know well into your inner private life.
As it stands, and your date develops into a full relationship, then if you have left the industry, he has no need to know, and that is probably what I would advise, as we don't know 'everything' in everyone's past that we date, so why should they know 'everything' about us. It's irrelevant because it was 'before' them.
that's my advice, but you have to do what you feel.
I once told an 'ex' and he ended up spitting in my face (I had escorted once in my life many years ago) but 'poshboy' who was a social retard, spat in my face and called me a prostitute all the time.
Sadly, it is a case of 'choose your confidantes wisely'.
Good luck though, I hope it goes well for you. xxx