I have to disagree with these fatalists. I have my secrets in my life, some that only a few others in a certain process or processes know, and well they were so long ago and never surfaced, pretty sure they never well. But for all that, I would say take the chance and don't tell. At least don't tell if it will make the difference in losing or keeping the situation the way you want. And be aware, that once told, it will be out. Like if you tell a guy, and he bolts, and his friends ask why, he is very likely to tell why. And even though it might have been long ago and far away, your isolation will be lost. If the guy you are worried about sees you as an angel, keep it that way. As long as there has never been a picture your fact out there, you can deny