"Then all of a sudden ... we find this attraction as being a reason to let her go," Ruth Hancock added. "I don't think that's justified."
They found a new dentist, they said.
Knight gave Nelson a month's severance for her 10 years of stellar work, but she decided to fight back.
"I think more than anything -- I was hurt," Nelson said.
In August 2010, Nelson filed a gender discrimination suit against Knight, seeking damages and lost pay, in Iowa District Court. The judge dismissed the case before trial.
Knight declined repeated requests for an interview. In court he didn't disagree with Nelson's characterization of the facts. His attorney told ABC News: "... she was not terminated because of her gender, but to preserve the best interest of his marriage."
However, Paige Fiedler, Nelson's attorney, said, "We had admission after admission after admission from the defendant himself that her sex played a part in his decision."
In September 2012 the Iowa Supreme Court heard Melissa's appeal. In December the seven justices ruled that although the one month's severance was "ungenerous," it is OK to terminate an employee "simply because the boss views the employee as an irresistible attraction." Especially since the boss's wife felt her marriage was threatened.
"I don't think the law is out of touch. ... This guy is a jerk, but being a jerk is not illegal," said Ilya Shapiro, a senior fellow in constitutional studies at the Cato Institute.
"You can fire someone for being tall, for being short, for cheering for the wrong team … all sorts of really stupid things that don't make any business sense, but are not illegal," Shapiro said.
Unless you are part of a "protected class," Fiedler counters.
"Your gender, color, race, national origin, religion, disability, age, pregnancy -- those are all thing that it's illegal to fire an employee for."