Eight-term Rep. Mark Souder will announce his resignation Tuesday after it came to light that he was conducting an affair with a female staffer who worked in his district office, Fox News has learned. Multiple senior House sources indicated that the extent of the affair would have landed Souder before the House Ethics Committee. Elected as a family values conservative as part of the Republican revolution in 1994, Souder survived a tough re-election challenge in 2008 and survived a contested primary two weeks ago.