I have arrived at this date from the information that the sons in the house in 1850 are from Theresa's earlier marriage to Bello. The Bellow boys are all born in Mighigan and all of Theresa's siblings are living there, so I guess they are married right there in the area.

Clyde becomes Kimball Twsp in 1855 : John Blockman Event Type: Census Event Year: 1850 Event Place: Clyde, St. Clair, Michigan, United States Gender: Male Age: 41 Race: White Race: Birth Year (Estimated): 1809 Birthplace: Vermont Household ID: 659 House Number: 659 Line Number: 24 Affiliate Name: The U.S. National Archives and Records Administration (NARA) Affiliate Publication Number: M432 Affiliate Film Number: 363 GS Film Number: 443578 Digital Folder Number: 004200037 Image Number: 00242 Household Role Sex Age Birthplace John Blockman M 41 Vermont Theresa Blockman F 23 Michigan Antwine Blockman M 4 Michigan Charles Blockman M 3 Michigan Marks Blockman M 5 Michigan Robert Blockman M 6 Michigan "United States Census, 1850," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MF8L-YPZ : 12 April 2016), John Blockman, Clyde, St. Clair, Michigan, United States; citing family 659, NARA microfilm publication M432 (Wa shington, D.C.: National Archives and Records Administration, n.d.).

Nextdoor to Joseph Bushaw possibly the brother of Theresa John Blackman Titles and Terms: Event Type: Census Event Date: 1860 Event Place: Town of Kimball, St Clair, Michigan, United States Gender: Male Age: 66 Race: White Race: Occupation: Birth Year (Estimated): 1794 Birthplace: Canada Page: 235 Household ID: 1696 Affiliate Name: The U.S. National Archives and Records Administration (NARA) Affiliate Publication Number: M653 Affiliate Film Number: 559 GS Film Number: 803559 Digital Folder Number: 005170193 Image Number: 00359 Household Role Sex Age Birthplace John Blackman M 66 Canada Theressa Blackman F 45 Canada Robert Blackman M 17 Michigan Mark Blackman M 15 Michigan Chas Blackman M 14 Michigan Antonie Blackman M 11 Michigan John Blackman M 9 Michigan Mary Blackman F 6 Michigan Laurence Blackman M 3 Michigan Lucy Blackman F 2 Michigan "United States Census, 1860", database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MWDY-J73 : 14 December 2017), John Blackman in entry for John Blackman, 1860.