I don't know if this is the same family or not, as the name that I find is Trepania, not Trepanier, but I have some information on a Joseph Trepania who stated in one of his memoirs that he was born "about 1815" at Three Rivers, Quebec. No mention of parents names. He came to Wisconsin in 1843, and although he spent some time in Sawyer Co., he finally settled in Springbrook, Washburn Co., WI. It is stated that he married a Margaret De Marie in 1851 or 52 and had two children, Alfred and Mary.
In another memoir, it states that Joe had also been married by Indian custom to two Indian women on the Lac Courte Oreilles Reservation and had a child by each. This appears to have been before he married Margaret.
Does any of this sound as if it is your Joseph? If so, please contact me directly, as there is extensive information to be shared.