do the rules apply to work/dates?

Part of my job involves talking to people on the phone for long periods of time over the course of several months, until eventually you learn pretty much all their neuroses and you recognize their cell phone number on your caller ID.  Because this is MY life, I spent the last 4 months working with a guy who within the first 10 minutes of us meeting in person, I found out that he was working around the clock, was no longer living at the address I had on file because he had (1) moved back in with his parents after (2) breaking off his engagement.  Clearly, this one had "winner" written all over him.  It actually got to the point where I would joke to male office mate that if I ever contemplated dating Client Guy, he would break the glass on an emergency kit designed specifically for this circumstance to prevent that from happening - broken engagement + neurotic + living with parents?  Totally my type.


Now, fast forward through 4 months of phone calls and excessive drama, to the point where there were several instances where I felt that Client Guy was on his cell phone with a noose around his neck and one foot stepping off the ledge, it's finally done and it's time to celebrate.  Client Guy was incredibly happy with the way things turned out, and wanted to take Boss & me out for drinks to celebrate.  A few hours later, Client Guy calls me back on my personal line (how DID he get that?  I have no idea) and updates me on his situation, which is followed by this exchange.

CG: Keep an eye out for the mail for the next few days - you're going to be getting a delivery.  Probably wine or vodka.  You guys were great to work with  - I owe you.

Me:  Thanks, it comes with the job, you were great to work with (etc, etc).

CG:  Can I ask you a question?

Me: (hesitantly) ummm, okay?

CG: Are you married?

Me:  (cracking up) No, I'm not married.

CG:  Well then can I take you out for drinks?  Like, take you out?  Like, not with Boss?  You know what I mean?

Me: (thinking to self, this deal isn't finalized yet):  Ummm....okay?

This was NOT in the job description.