Yes, yes he did. I have worked for him for 10 years and would never in a million thought this would happen....I edited my original post to provide more info.
Think of it this way. You still got it woman.
It was across the line, obviously. I mean look you never know. Maybe his wife who you respect hates him. Maybe he had a weak moment. Maybe he's a fucking serial philanderer. I mean there's no telling.
You don't have to hate or fear him though. All the broken social codes aside, that was a compliment. And not just "oh baby you're hot". It was a compliment about the nature of your friendship. He didn't do it cause he's horny. I mean, probably.
It really can all go away. Don't shame him with it though. And you can without meaning to. Tell him some version of "Look, that never happens again. But we're still friends, yeah?"
Unless he's a complete idiot he'll take that deal and thank you for it. And then it'll be weird for about a month. And then it won't be.
People make mistakes. If there's not a history of this (obviously he's been thinking this about you for more than just the day it happened. That's how men are) then really you shouldn't worry. Why did he act on it that day and not any of the other days? I dunno, you'd really have to ask him.
Some questions though you don't actually want the answers to. It may be that he's thinking about retirement or afraid that he's about to get laid off, it's equally likely something like that as anything nefarious... so you know, seize the day make your play. It's better to regret something you did than something you were too afraid to.
And yes, he did it as clumsily as a teenager. I'm not saying you have no right to be offended or angry, only that you don't need to be afraid or protect yourself with hate.
Covering your ass is probably wisdom, as well, like the other guys have said. But don't let him see you do it. That'll go south quickly.