Just Cause I'm Nice Doesn't Mean It's a Crush

My coworker at work is going through a divorce after 13 years of marriage. I feel really bad for the guy so the past couple of months, I've been talking to him to make sure he's ok. Once in awhile, I'll compliment him on how he's a good catch just to boost his ego. On Monday, we were talking about relationships and he told me that I was a good catch. How I'm smart and beautiful and he even told me that a few guys around the office do notice me for my wonderful qualities. Later on in the conversation, he said we should have lunch sometime and I said I was free on Friday. His response? "Ok! It's a date!" I tried to not be too obvious that I didn't want it to be a date by saying, "uhhh, we can invite the guys. I'm sure they'd like to join us." Then he says that it won't be a date anymore. How can I be completely oblivious?! I tend to flirt on accident because when I talk to people, I'll touch them once in awhile. I even do it to girls. And clearly I do not like girls. It's just my way of showing the person that I'm really listening to them. So now it's awkward whenever I see him because I don't feel the same way. I once told my other coworker that I would never date a coworker, but lately I've been noticing this other coworker of mines. He's pretty cute and I'd break my rule for him.