Pie - First, I'm no Eminem fan, in the least. But, I can tell you my H did the same thing 8 years ago. He sent me a song that still brings tears to my eyes today when I hear it on the radio. To say how sorry he was. So maybe your husband is trying to tell you through music/lyrics how he feels. That wouldn't be so surprising.
But, Pie, it's a song, not a committment. If it helps you get through the day and keep a flame of hope alive in your heart than it's worth every word. Just don't put too much expectation into it.