I had the impression that the Chinese consulate, at least the one in NYC, does not provide changing stamp on the martial status anymore. Not 100% sure though. You may want to double check it.

My personal experience is that no need to do that. After I got married in US, I have travelled in and out of China many times on my unchanged passport, and have never been questioned at all. I even used my passport to re-install my Hu Kou page in BJ, on which I fill in the status with married.