I think if you heard the Whitney Houston version of this song you'd recognize it as the theme song to the movie "The Bodyguard." It surprises many people that the original song was written by Dolly Parton. In either case, the message, while open to more specific interpretation, is pretty much the same.
The speaker is lamenting a love that she is saying goodbye to, but not because she's stopped loving the "you" in the song. It sounds, instead, as if the "you" has stopped loving the speaker. Lines like
I would only be in your way
We both know that I'm not what you need
all suggest that the speaker's love for the one she is singing to is unrequited (which means love that is not reciprocated). I think if you read through the lyrics (or better, listen to a version of the song) you will be able to come up with an interpretation that is similar, but perhaps a little more personal.
I cannot even think of being away from your lovable memories, because it instills in me moments of heavenly bliss.