Applying for green card within the US?

[alex.domini]

My fiancé is from Argentina. We are set to be married in a few months. Right now he is here on a tourist visa. He will be going back home for a month to see his family and then will return. When he does return, will he still be on a three month limit of the tourist visa even after we are married?

How soon after being married should we start the green card process?

We want to avoid being apart, and someone else has told me that if we get married, he will need to wait the duration for the green card or visa to process in Argentina. We do not want to be apart that long, so is there any way he can stay here after we are married while we wait for the green card to go through?