When Is The Relationship Over?

How does one get a person in a relationship to finally admit the relationship is over?
It's not over because one is bored , mad or even cheating it's over because it died a natural death.

It was born of a natural attraction in all ways. Enjoying each other's company at all times including hot, wet delicious sex. Sharing dreams that they knew couldn't actually happen, actually more "wishes" than "hopes".The joy of living was experienced whenever they were together.

This experience was lost a little at a time, bit by bit, until all they had, all that made them a couple was gone. However, they acted as if nothing had changed pushing the reality of it to the back of their consciousness subconsciously thinking if they wouldn't recognize what was happening then it didn't happen. But of course it did happen, their relationship was over.

They never touched, not even as little as hand holding and embracing was anathema. Future plans were discussed in the singular never as a couple. There was no "we" only "I" in any plans future or present.

The time had come for a reality check in order to stop living a lie , to get on with their lives which meant drifting apart recognizing that their journey as lovers was over and at the most they were friends, lovers no more. Divergent paths had to be taken if they were to reach fulfillment in their lives.

The question is how? How to do this thing without destroying what was beautiful, how to cherish the memories recognizing their relationship helped them be who they had become and now it was time to move on.