Amy wouldn't benefit by calling and slandering Duncan (an athlete who hasn't raised any red flag about his sexuality) gay. If she wants any sort of pity from the judge, she, like most women can pull a lot of cards to the table. Being an NBA athlete, fidelity is an issue, so citing that as the reason of irreconcilable difference is really the easiest choice but to make it really convincing, replacing an alleged gay partner to a woman would be a home run for her defense. Amy could also state her marriage with Duncan lacks equality or commitment and let the issue die as time goes by.
I'm not saying Duncan is gay, but in civil cases, involving gay accusations, it can backfire on so many ways, most couple just settle to avoid airing out any dirty laundry. The fact that Amy was ready to go to legal war with Duncan speaks volumes of how much dirt she probably has on Duncan, Tim and his lawyers panicked and enforced the gag order in return.
Amy could very well be just another lying out to destroy the sterling reputation of Duncan, but if you flip the script and be objective about it, Amy's accusation is probably true in which Duncan does enjoy baseball bat action on the side. Truth is we will never know.
As a straight man, I for one will never buy a buddy of mine a condo, that I can tell you.