A "perfect couple" describes two people in a relationship who seem ideally matched and happy. Others view them as balanced in values, love, and support. It can be sincere or just a glossy image people show to others.
He didn't mind if she hated him. They were never going to be a cute romantic couple like Sam and Astrid. Clean-cut, righteous, all that. The perfect couple. He and Diana were the imperfect couple. Michael Grant