In fact, contrary to your expectation, talking about the issues that gave rise to PTSD, should help overcoming it. But, it should no be talked about all the time. It should be discussed half an hour daily one to two times. rest of the time, you mind other business. The fact that your wife does keep on speaking about this might indicate that she also has been perhaps traumatised, in the inner psychologial sense. Therefore, I would suggest both of you, to seek a psychiatrist / therapist who might put you on medication, too. This helps Separation is not the solution and might worsen the issues, in such cases