Complex sentence: MacDonald was romantically involved with time as leader of the federal NDP, Alexa McDonough prior to his 1997 candidacy but split up prior to the 2004 federal election.
Split into simpler sentences: MacDonald was romantically involved with time as leader of the federal NDP, Alexa McDonough prior to his 1997 candidacy. However, they split up prior to the 2004 federal election.