By Zach Koons A four-decade relationship between ESPN and the Big Ten appears to be over. ESPN has pulled out of media rights negotiations with the Big Ten, ending a four-decade relationship between the network and conference, according to Sports Business Journal’s John Ourand. The Tuesday morning update comes after previous reports indicated that the negotiations between the two sides were hanging by a thread. ESPN then reportedly turned down a seven-year, $380 million offer from the Big Ten for about 13 games per season, according to SI’s Ross Dellenger. That package would have been about ha…