Unsure why there's confusion. He's still not over you, desperate for you to have a change of heart so that the dream/expectation of sharing his life with you returns as reality. He tried to move on by finding someone he liked but since he hasn't developed the depth of feeling with his new friend that he shared with you, he's wavered, decided this wasn't what he wanted, yhat he was fooling himself, and returned to hoping to change your mind.
Since you are convinced that you have done the right thing you simply have to be firm and not give any unintended hope. Sometimes it is easier to have a period of total non-communication until the situation has been truly accepted by all.