Unlike what most people think here, that the the girl told him she was dying literally right after he proposed, I think hes telling about their lives. They met young. Maybe highschool sweethearts. He proposed, she excepted and they got.married, had a baby boy but when their son was still a baby, she found out she was sick and that she wasn't going to live much longer. And after losing the woman he loved more than anything, and knowing the feeling, hes telling his son to never fall in love because he doesn't want to see him hurt.
Unlike what most people think here, that the the girl told him she was dying literally right after he proposed, I think hes telling about their lives. They met young. Maybe highschool sweethearts. He proposed, she excepted and they got.married, had a baby boy but when their son was still a baby, she found out she was sick and that she wasn't going to live much longer. And after losing the woman he loved more than anything, and knowing the feeling, hes telling his son to never fall in love because he doesn't want to see him hurt.