work husband

I’ve been working for a construction company in their office and have been becoming closer to this guy. We went to high school together and have known each other for over ten years (family friend) but haven’t talked much until recently. We have been spending more time together because of work and I think he may have a crush on me, but I’m not sure how to handle it, since he is very shy. The other guys I work with say that he’s liked me for years. I don’t want to ruin our professional relationship.. Any advice?