Requirements for Citizenship

[The_Sentinel]

I got my Employment based GC a year ago. I got engaged and will be marrying a US citizen. I know that the spouse of a US citizen is eligibel to apply for Citizenship after three years as a LPR. Does that three years count from the date I got the GC or three years of being married to the spouse? Which means about four years from the date of becoming a LPR?

 

[Yili]

What date is the starting date of this five year period?

I-485 approval date or pp stamp date?