It's saying, in my opinion, that it should be him that she's going out with, and not who she's actually going out with. He's loved her for so long, and she never knew. He's frustrated with himself because he had his chances, but never told her. He's upset because that could have been him that she's with,
It's saying, in my opinion, that it should be him that she's going out with, and not who she's actually going out with. He's loved her for so long, and she never knew. He's frustrated with himself because he had his chances, but never told her. He's upset because that could have been him that she's with,