Imagine a married man with three kids.

Have an affair with a mistress. She's his true love. Hard to leave his wife and kids, and that's almost impossible.

The mistress loves him too. So the man has to choose between his present wife and his lover, hence the phrase "torn between the lover and the love you leave behind".

At the end, his mistress left him, a devastating ending for him. He keep remembering her for all of his life, even after his mistress married with someone else.

Remember, too much love will kill you.