Yep, "Then You Can Tell Me Goodbye" is a great I-VI-II-V7 '12/8 feel' LOVE song that remains at the TOP of my performance set list as well. This one is GUARANTEED to fill the dance floor with couples smooching. I enjoy using the harmonizer to emulate the vocal harmonies of the Casinos.
I think Glenn & UD are BOTH right. From the singer's POV, this is a LOVE song through & through, promising his girl a lifetime of devotion, but it's also clear (to me) that the singer feels there's at least 'some reservation' on her part about such a commitment.
The power of a singer is having the ability to personally interprete and deliver the(lyric) line to reflect their own POV.
The key to achieving this (for me) is first MEMORIZING the words completely AWAY from the keyboard. DON'T sing the melody, but speak them like you're delivering lines in a play. Set up the scenerio (scene) and figure out the: who, what, where, and why of the setting.
Example: My name is John, and Mary and I have been dating for a year. I've been madly in love with her since we met, but though she told me that loves me too, she had told me in the past that she wasn't ready (yet) to make a lifetime commitment (marriage). It's a warm romantic evening on our 1 year anniversary, and I've finally decided (with engagement ring in hand) to pop the question (delivering the words of the song).
Once I'm able to speak & deliver (express) the words naturally and convincingly from begining to end (fully memorized), phrasing & delivering them with a natural cadence, then it's finally time to add the melody and actually SING them.
I guarantee your songs will have much more power and meaning (to both you and your listening audience) if you apply the above techniques .
Scott