I think Paulus has it dead on.

The hint is in the title...

Casey is heading home after being with his lover. He has decided that is the last time he will see her and on the trip home, he stops off at the pub... can't face going home to his wife and children... the sadness of resigning himself to the life 'a family of your own'.

The 'choruses' of the woman is him thinking back to her, the things she said to him in that last meeting. She knows he is unhappy in this life and wants him to stay with her 'Casey it's so sad to be alone' but he has made his decision.

Such an amazing song.