"I learned through experience that it doesn't work for me to talk about my personal life," the actress, 36, tells Glamour in its October issue.
"I've had earlier times in my career when I did talk about it," explains Washington, who appeared on the cover of InStyle Weddings in 2005 while engaged to actor David Moscow. The couple split in 2007.
"But I couldn't just turn around and say, 'I only want to talk about the good stuff, but not the bad stuff,' " she says. "So I just thought, 'OK, no more.' "
Peggy Sirota / Glamour
"I'm walking around in the world with my ring. And when people say congratulations, I say thank you," Washington tells the magazine, on newsstands Sept. 10. "But I'm going to continue to not talk about it and just let it unfold."
Not that she's judging actors that do talk about their personal lives.
"I don't want to sound smug about it … but the point is to do what's best for me," she explains.
"I have girlfriends in this business who talk about their personal lives, and it works for them, and I love it. But not for me."