I think he loved his girlfriend very luch, but didn't show it enough. Then, she left him for some other guy, a mean one. He laughs at de first boyfriend, because he has "won" the girl. He says that de first boyfriend should have loved her more. The first one gives up waiting for her. The girl realizes that the first one really loved her, while the one she's with now is a jerk. So in the end she is punished for being so blind.
But the comment of Blue Bit is also possible.
I think he loved his girlfriend very luch, but didn't show it enough. Then, she left him for some other guy, a mean one. He laughs at de first boyfriend, because he has "won" the girl. He says that de first boyfriend should have loved her more. The first one gives up waiting for her. The girl realizes that the first one really loved her, while the one she's with now is a jerk. So in the end she is punished for being so blind. But the comment of Blue Bit is also possible.