Thinking about the layers of the situation, I honestly believe staying silent would be a worse look for her character, actually.
Staying silent signals to me that the only reason she spoke up about Emile to begin with was because she was expecting that her lie through omission would never come to light.
"Oopsie, I forgot to tell the most important part that recontextualizes everything, but I guess I'll use it as an excuse to air dirty laundry about our 10-year relationship." isn't nearly as scummy as "I intentionally lied about somebody, hoping they'd end up as a corpse incapable of calling me out for it."
That said, I'm a cynical bastard, so staying silent would probably be the better look to most people on the internet.