Should i be mean, or let him go peacefully?

I think you already learned a valuable lesson from this whole situation... you learned that you are worth something and don't have to be treated like left-overs. Stick to your guns and tell him that you don't need him and move on. Life is too short to live in the past and isn't worth the energy to worry about teaching him a lesson.. he'll never learn and if you give in.. then all you are showing him is that you are weak and vunerable.