What you should do now is move on. Not only is he taken, he's a liar and a cheat. You don't need people like that in your life.
Single" means not married. He told that part of the truth to you. In a relationship he is and that is what he should have told you.
Perhaps he wants to see if he likes you better or for longer than he can see himself with this other girl. Get his intentions down and if he falters in his explanation, toss him to the curb.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.