@coleg,
I'm trying to wrap my head around how you think a work romance with this person is a possibility.
Let's start with... You are her father's age. Yeah, just let that sink in a minute.
Then, on top of that, you are married. As in, yes, a WIFE. Which, I'm guessing, hasn't been told of your flirty, laughter filled behavior with the work colleague. I'm sure if you asked your wife if she thinks the "hot and cold mind games" may come to a mutual understanding for an office romance, she'll have plenty to say about that.
Next, we'll move to your atrocious behavior in the conference, where you proceeded to tell the Office Secretary about her job description as if you were her boss and signed her paycheck. And was proven wrong. If I were YOUR boss, I'd have fired you for that. If you can't manage to communicate effectively without having "raise your voice" to the person who is the company's backbone then you're not working for me. You acted poorly, which you acknowledge and that's good.
What isn't good is you thinking she cares about you in any thing more than in a professional manner. You've proven, not only to her, but to other people as well, that you think you are somehow superior in stature in the company. They laugh about you and you caught them doing it and it sailed right over your head. She now has seen your true colors, and she now knows to stay away from you.
This isn't sexual tension, it's just plain tension from having to work with someone she doesn't like but has to put up with. You, the annoying salesperson who thinks he's better than the rest and clearly, isn't.
Just leave her alone. Before you get fired for Harassment.