i don't know what should i say, maybe sorry isn't what you want to hear. since you have told him, your boy, you used to be in my room, then just needn't think is it good to be frank to him or not. because you've already told! just go face whatever will happen next. don't blame. i know you just would like to be frank to whom you love! nothing is right or wrong. it just happened this way...
god knows what will happen!