we can't be together, so we have to leave.
parting is bound to be very painful, and I can't bear to send it away, so I quietly left and left my memories in my heart. Keep that man in your heart.
I am willing to forget you and watch your back go away. If I give up you and have a bright future, I would rather hide you in my heart and never let you know this love.
that's probably what it means.