Fetish, thank you for your suggestion! I presented it to my sub exactly as you said, with an attitude of "there's this guy at work who thinks he can serve me". My sub reacted quite positively, actually- he asked me what sort of things the guy at work was doing, and then he told me how he could do it better, and it was actually a really big turn-on and we had a very nice night

As for confronting the male at work, I think I will continue to try to simply not respond as best as possible and see what happens. There hasn't been anything overly inappropriate so far, and now that my sub knows, I feel so much less guilty and now I think it will just make the day rather entertaining.

Well, when he said that he didn't tell it to me, personally, we were all talking in a group when he disclosed that information...
I'm curious. Was he the only male in that group?
Mostly; my male "supervisor" was there but he says very little to anyone and just does what I tell him; most of the rest of the office ignores him (and it's funny because my relationship with him is completely D/s, I guess, but in an entirely non-sexual way, completely platonic, he's married with a new baby), but other than him, yes, it was only females around, why, what were you thinking?