Awwwwwww. We're shocked, shocked we tell you:

Indiana Republican Rep. Mark Souder announced Tuesday he would resign from Congress, effective Friday, because he had an affair with a staffer.

The eight-term congressman apologized for his actions but provided no details.

"I am so ashamed to have hurt the ones I love," he said at a news conference in Fort Wayne. "I am sorry to have let so many friends down, people who have worked so hard for me."

... Souder, 59, said he would not be a candidate in the fall election. It will be up to Republican Gov. Mitch Daniels to decide whether to call a special election to fill the vacancy or wait until the November ballot.

"I sinned against God, my wife and my family by having a mutual relationship with a part-time member of my staff," Souder said. "In the poisonous environment of Washington, D.C., any personal failing is seized upon and twisted for political gain. I am resigning rather than put my family through a painful drawn out process.