Hi,
Since you didn't include where John was born, I assume you either don't know or somewhere in Utah. Prior to 1905 in Utah, you have to know the county the person was born in to be able to order a birth certificate.

I found two other possibilities for John Simmons who married Alice.

John James Simmons in 1870 living in Morgan, Utah Territory.
b. UT, 3.

John Simmons in 1870 was living in Salt Lake City with his family, b. UT, 3.

You can apply for a copy of their marriage license in Weber County as shown at http://archives.utah.gov/research/guides/marriage.htm. Successful Searching!