Montgomery Gentry‘s Eddie Montgomery was served divorce papers from his wife, Tracy Montgomery, on Tuesday night (Nov. 30). In several candid messages later posted on Twitter, the singer speculated the divorce stems from her inability to cope with his recent cancer diagnosis. The legal papers were presented to Montgomery at a steakhouse he owns in Harrodsburg, Ky. The couple, married for more than 20 years, have four children and one grandchild. On Nov. 18, he revealed he has been diagnosed with prostate cancer. He plans to undergo surgery later this month. As previously reported, Montgomery Gentry parted ways with their longtime record label, Sony Music Nashville, in September. The duo’s tour dates for 2010 will conclude on Saturday (Dec. 4) in Charlotte, N.C.