You are wrong. You lied at immigration. That is a serious criminal offence.I doubt PR will be revoked or banned because criminal offenses are more in that line. Just a marital status update failure wont be that harmful. Will talk to an attorney today.
When you landed, you were asked your marital status. The form said single. If you said single, you knew you were lying. If you said married, the officer would have asked why the form was wrong. So you didn't tell the truth.