"If you didn't leave at that time, would it make any difference to our relationship?"
"If at that time, you had the courage to get on the subway train, I would've stayed with you forever."
When I first heard that, I didn't read too much into it. It just sounded like regrets on top of regrets, a load of "What-ifs".
Later while listening to Eason Chen's main title song: 我们 that I saw the following YouTube comment, and everything clicked into place.
"This might be the difference between man and woman: While you are happy and contented, I have nothing. I really do not have the courage to get on that train, afraid you will follow me and live a terrible life; Meanwhile, she wants to see the attitude and determination in him, hope that he love without any doubts or fear. Hence, if you make this step and get on the subway train, I will follow you for the rest of our lives."