I agree, your heart and mind are telling you that you aren't ready to date. Tuck this guy away or just do things as a big group with him involved. He wants more (why wouldn't he? You rock!), why hurt him and make yourself uncomfortable?
Guys and girls as friends? I sure hope so. I work with 95% males, married, divorced, single, all kinds. Some of us go to lunch (as groups with other females) on a weekly basis.
The problem is, for me, I am completely still entangled with my xh. I still love him, think about him, am so very sad about the divorce, etc. Even though, daily, I feel pretty good, there is soooo much about me that isn't ready to move on and date. It wouldn't be fair to me or anyone else.