Sounds like high school for me, lol. I'm not kidding, it was about once a week people would ask if we were dating. I would get a little angry, honestly.
Not saying that what happened to me will happen to you, but HE actually asked this of me at first, and I told him no. Then he asked me again, and I said yes. So we dated for 6 months, broke it off when I went to college. I came home, and we started dating again. Broke it off one more time, and now he swears not to ever date me again, lol. I can't speak for your relationship, but the one I've got with my best guy is a pretty damn good one. Dating only taught us more about each other, and now even when we're not dating, I feel like we're closer than ever before. Did I hurt him at times? Yes. Do I regret doing it? No. Does he regret it? No.
If you've got anymore questions on this, I'll be more than happy to answer. I've been going in circles with my guy for a little more than 6 years now, so while I may not be a complete expert on dating friends, I'm pretty close.