Because Utah did not issue marriage licenses or certificates until 1887 we have no record of the actual marriage and my search of the IGI Sept. 2004 under John Erik Forsgren as well as a 2010 search of temple records in new Family Search does not list a sealing to Ingeborg; It is possible that the sealing, if there ever was one, was canceled and therefore would not show up on the IGI.
CENSUS: 1860 U.S. Census of Moroni, Sanpete, Utah Territory. Rll M653_1314. p. 661 Image 123 (taken 18 June 1860)
Fosgren, J. E., male, age 44 <1816>, painter, born Sweden
Fosgren, Ingleburg, female, age 56, <1804>, born Denmark
Fosgren, Wm, male, age 11, born Denmark
Fosgren, Peter, male, age 10, born Denmark
Fosgren, Charles, male, age 10, born Denmark [this is incorrect]
Fosgren, Jno, male, age 4, born Utah
Fosgren, Alice, female, age 5, born Utah
[NOTE: Charles, Alice and John are ALSO listed with their mother Sarah in the Brigham City Census taken later on 25 July 1860, but they are mistakenly listed as Clappers. It is not known for certain that the children were physically present in either home on the days the census takers came by. Their instructions were to have people list all inhabitants of a house as of the official census date, which in this case was 1 June. Some historians have alluded to a common practice of claiming people who were not actually physically present - mainly to help inflate or "impress" greater statistics in preparation for Utah Statehood].
Update Dec 2010. Again, thanks to Laurie J. Bryant who took the time to do the sleuthing I had only thought about doing we can probably identify Ingeborg as the Ingeborg Petersen who arrived in Utah with the Robert F. Neslen Company of 1859. This is the only Ingeborg of appropriate age in all the overland trail lists. "That company list also includes Ingeborg's son, Peter Wilhelm, age 8, and a boy named Hans Peter Petersen, age 10, who is not listed as part of any family. These boys, a year older and with their names Americanized to William and Peter, would be the other two children in the 1860 Forsgren household." (Quote from Laurie Bryant's manuscript "A Rascal Among the Faithful). After the divorce of John and Ingeborg nothing more is known about her or her children.
Court Record of the divorce decree
Sanpete County, Utah, Probate Court Minutes, May 8, 1862.
Utah State Archives, series 17694, reel 138851