To tell him or not to tell him...that is the question?

Ok my ex and I have become very close friends since our relationship ended. And he wanted to give us another try at the start of the year but i was involved with someone else so i said no. Lately we've been getting very close and i've gotten stronger feelings for him then i had before, he's the only one who can make me laugh the way he does and we can tlk about nothing for hours. I know he likes me too, but im really scared to give us another try incase i hurt him again (im very indecisive). Another complication is he lost his virginity to my best friend after we broke up so idk if im ok with that.What should i do, should i risk our awesome friendhip by telling him or keep my mouth shut to protect it?