Looking for James Martine Kershaw Aka James Martine Provost

My g-grandfather was originally born James Martine Provost in New York. He then met an only child and in order to marry her, the father said he had to change his last name to Kershaw. However, she married someone else after he changed his last name!

He married a young lady from Scotland by the name of Margaret Ellen Wilson in approximately 1845.