It seems yourFrederick was married twice. Info as follows:
1900 WI, Adams, New Chester, Dist 4
Hubbard, Frederick J. Aug 1839 60 married 18 yrs. NH NH NH Farmer
Fannie E. Dec. 1861 38 married 18 yrs. 2 born 2 living WI WI Scot
Roy A. Jan 1885 15 NH
Alfred S. Aug 1874 25 NH
Jessie J. Jan 1891 9 NH
Aldrich, Jessie A. MIL Oct 1844 58 Wid Scot Scot Scot Immigrated 1850
1880 NH, Cheshire, Walpole, Dist 67;
Hubbard, Frederick 41 Dealer in Horses NH NH NH
Julietta, 40 NH Mass NH
Walter F. 19 NH
Alfred S. 5 NH
Catherine Mother 81 NH NH Mass
1870 NH, Cheshire, Walpole
Hubbard, Frederic 31 Farmer RE $1000 PP $800 NH
Julia 31 NH
Walter S. 9 NH
Gils? Marie 26 NH
Gils? Josephine 21 NH
NOTE: While the last name of Josephine and Marie is not legible on the census, it is quite possible that they are Julia's sisters.
1860 NH, Cheshire, Westmoreland
Hubbard, Frederic 21 NH PP $300
Julietta 20 NH
Catherine 61 NH
Field, Samuel Farm Labor 21 NH
1850 NH, Cheshire, Walpole
Hubbard, Catherine 51 RE $200 NH
Levi 18 NH
FREDERICK 12 NH
Considering that Frederick lived most of his early life in the same county, it is a safe bet that you should be able to obtain a marriage record for Frederick and Julietta.
I went back one more census to 1840 and found several 'Hubbards' living in Cheshire county.
Since all but Isaac had male children aged 0-5, it is difficult to say which one could have been Frederick's father. It is quite possible that the Catherine from that census was aged 40-50, that she was a widow in that census also.
However, going back to the 1830 census gave me a different idea of who might have been Frederick's father. There are only three 'Hubbards' listed for that census in Walpole twp.
By checking the ages of the children, it seems that Daniel is the most likely candidate for the father of your Frederick.
Now regarding your Frederick and Fannie (Frances), she was born and from what I was able to ascertain, she lived her early life in Wisconsin exclusively. You can be reasonably sure that they were married in Marquette county, as well as Amasa and Jessie Aldrich, the parents of Fannie.
I hope you find this helpful. I wish you the very best of luck with your continued research.