A person cannot live without starring his partner. He just feel like he is seeing the best person in the world.
He feels like he is out of his mind. He does stuff which are not appropriate or not practical but still he does to make his partner happy.
He just keeps on thinking about her. Think of past talk done with her or future talks he wants to do with her.
He always wants his partner to be happy. Does so much innocent thing just to see smile on her face and keep her happy.