Why it could work: Mark is one of Julianne's oldest buds (so you'd think we could find a picture of them together!) and friendship is a great foundation for romance. You're supposed to marry your best friend, right? Plus, Mark obviously shares Julianne's love for "Dancing With the Stars." When they were kids, they even had a pop group with Derek Hough called 2B1G (two boys and one girl) and dated. Mark said of Julianne, "She was my first love."