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

Souder said in a statement provided by his office that he has "sinned against God, my wife and my family by having a mutual relationship with a part-time member of my staff."

He scheduled a news conference in Fort Wayne today to discuss his decision.

Souder, noted for his conservative views, won a bruising Republican primary on May 4 to be nominated for his ninth term representing northeastern Indiana.

Souder, 59, said he also would not be a candidate in the fall election.

"I believe it is the best decision for my family, the people of northeast Indiana and our country," he said in the statement.

"In the poisonous environment of Washington, D.C., any personal failing is seized upon, often twisted, for political gain," he said. "I am resigning rather than to put my family through that painful, drawn-out process."

Souder won the Republican primary over car dealer Bob Thomas, who spent much of his own money on television commercials portraying Souder as a career politician who wasn't a true fiscal conservative. Souder countered by emphasizing his A-plus marks from the National Rifle Association and 100 percent rating from the National Right to Life Committee.

Souder had been expected to face a stiff challege from Democrat Tom Hayhurst, a former Fort Wayne city councilman who lost a close race to Souder in 2006.

Souder did not provide details about the affair.

"As I leave public office, my plans are focused upon repairing my marriage, earning back the trust of my family and my community, and renewing my walk with my Lord," he said.

 Souder has been married to his wife, Diane, since 1974, and they have three adult children.

 Souder's statement

 The complete text of Souder's resignation statement  follows:

 "It is with great regret I announce that I am resigning from the U.S. House of Representatives, as well as resigning as the Republican nominee for Congress in this fall's election.

I believe it is the best decision for my family, the people of northeast Indiana, and our country.

I will submit my resignation to Speaker Pelosi effective this Friday.

I can never fully thank all those who have worked so hard, given so much and supported me through eight contested primaries and eight general elections.

Only when you have been the recipient can you really feel the humbling power of such generosity.

It has been a great honor to fight for the needs, the jobs, and the future of this region where my family has lived for over 160 years.

It has been all consuming for me to do this job well, especially in a district with costly, competitive elections every two years

I do not have any sort of 'normal' life - for family, for friends, for church, for community.

To serve has been a blessing and a responsibility given from God.

I wish I could have been a better example.

I sinned against God, my wife and my family by having a mutual relationship with a part-time member of my staff.

In the poisonous environment of Washington, D.C., any personal failing is seized upon, often twisted, for political gain.

I am resigning rather than to put my family through that painful, drawn-out process.

Diane and my family were more than willing to stand here with me.

We are a committed family.

But the error is mine and I should bear the responsibility,

Not only am I thankful for a loving family but for a loving God.

My comfort is that God is a gracious and forgiving God to those who sincerely seek his forgiveness as I do.

But I am so ashamed to have hurt those I love.

I am so sorry to have let so many friends down, people who have fought so hard for me.

The ideas we advocate are still just and right.

America will survive and thrive when anchored in those values.

Human beings, like me, will fail, but our cause is greater than individuals.

It is based upon eternal truths.

By stepping aside, my mistake cannot be used as a political football in a partisan attempt to undermine the cause for which i have labored all my adult life.

I love this area.

This is my home.

It has been such an honor to serve you.

For 16 years, my family and I have given our all for this area.

The toll has been high.

As I leave public office, my plans are focused upon repairing my marriage, earning back the trust of my family and my community, and renewing my walk with my lord.

I humbly ask you, for the sake of my family that you respect our privacy in this difficult time.

I have no further comments."