A stunning revelation in a Homewood murder case.    Prosecutors say the Rev. Richard Shahan killed his wife Karen, so he could start a new life, with his boyfriend.   The Jefferson County District Attorney's office cited more than 3,000 of Shahan's emails, saying they indicate the minister planned to travel to Germany and Kazakhstan, before ultimately settling in the UK, where he intended to marry the unidentified man.   A judge  set bond at $100,000.   If he's able to bond out, Shahan would remain under house arrest.    Karen Shahan was found murdered at the couple's home last July.   Authorities say she was stabbed to death.   Shahan, a former associate pastor at the First Baptist Church of Birmingham, resigned Dec. 31, a day before he was arrested at the Nashville airport, attempting to board a flight to Germany.