Does this mean he's not sure?

It means you hurt him and it is hard for him to open up and share his heart with you. He was considering whether or not he was ready to commit to loving you, and you showed him you didn't mean it when you said you loved him. Love is less than 20% physical (affection, sex, etc.), around 20% emotional (feelings), around 30% mental (decision to risk and commit) and more than 30% spiritual (the God level connections that cannot be described).
He was considering opening his heart to you, and you proved you could not be trusted with it. It is up to you to tell him why you can say you love him and give someone else your number but, you will have to earn his trust back, before he will even consider opening up again.

Its wrong to make love with some one when they don't love you back.

no I think he means it he's just upset or jealous that you gave another guy our number!