Sci-Fi short story read in a collection. Couple with crystal tree that reflected their emotions

Question

I am trying to track down a short story collection (Sci-Fi) that contained this story.

A couple have a crystal tree that reflects their emotions. They are very proud of the tree, even though they begin to not get along and even begin to loathe each other. They only show the tree what they want it to see and end up staying together longer because of the tree. So in effect the tree is only reflecting their behaviors not their true feelings. I think the tree thrived when it reflected them doing well, but when they did not do well the tree would not do well either.

The reader who asked me to help find this short story says he read it in the period from 2002 - 2005 but does not feel sure if it was written then or earlier. He thought it might have been in one of the "best of" sci-fi writing titles.

Answer 1

This answer is a duplicate of https://scifi.stackexchange.com/a/261065/16171 which is about the same story. The boldface quotes are from that question rather than this one.

This is "The Synergy Sculpture" (1978) by Terrence L. Brown. It was original to Orbit 20 and never reprinted.

a couple whose prized possession is semi-living crystal structure that is sensitive to their relationship

'The Synergy Sculpture is not a toy. It is a sensitive scientific instrument designed to aid couples and groups in becoming more aware of their emotional interactions. The Synergy Sculpture measures emotional interactions among the two to ten people to whom the unit is tuned—not individual emotional states. It has been used successfully by hundreds of psychotherapists throughout the world as a monitor of the growth of couples and groups toward emotionally mature relationships!'

it grows and maintains its beauty as a reflection of how good their relationship is.

“Right,” said Mary enthusiastically. “And the better the vibes between us, the more complex, colorful, and beautiful it gets.”

Because they are so invested in their crystal, they act happy and content while secretly loathing each other... effectively, slaves to the crystal by choice.

“It’s so sensitive,” John said. “We destroyed it with our argument.” He turned to Mary. “I’m sorry, honey. I should have thought before I snapped at you.”

“It’s okay, I understand.”

and

“Let’s make love,” he whispered. He kissed her neck.

“I’m tired,” she said, turning away.

“Come on, think what it’ll do to the sculpture.”