A lot of this is head cannon- (mal and Harry dated before mal left the isle.)

Harry sat on the docks, sitting on the edge beside the water near Uma’s Ship. He looked out at the isle quietly- quiet- for once in his bloody life. He looked like he was deep in thought. Mal had recently been chosen to go to the isle- mal and Harry used to date and weren’t left on good terms- they’d argued and broke up just before she left.