Oregon’s embattled governor John Kitzhaber has resigned amid scandal, facing a criminal investigation into allegations of public corruption. The governor’s fall from grace involves his relationship with his fiancee, Cylvia Haynes. The couple are being investigated for possibly misusing their political influence for personal gain. The resignation will take effect Wednesday, at which time Secretary of State Kate Brown (D) will take over as governor.

Kitzhaber’s Friday resignation ends one of the longest political careers in Oregon history. He was sworn in to serve an unprecedented fourth term as governor just last month. Investigations, intense scrutiny by the media and rapidly increasing political pressure to resign finally proved too to be too much. During the week he decided to resign, changed his mind, then gave in to pressure and stepped down, even as opponents were preparing to collect signatures for recall petitions.

Pressure on Kitzhaber and Hayes mounted earlier this week, starting with the criminal investigation opened by the state attorney general. Another investigation has reportedly been launched by the FBI. Then, on Thursday, he was called on to step down by the two top-ranking Democrats in the legislature.

The investigation center around Hayes, who has earned more than $200,000 as a consultant during the same time she was acting as an adviser to the governor and a private consultant. Even during the most recent election Kitzhaber was plagued by questions about whether his fiancee, whom he lives with, had violated criminal laws or ethics rules as she acted as his adviser about clean energy issues at the same time she was working as a consultant on the same topic and acting as first lady.

Kitzhaber said that he was sure he would be exonerated, saying he was confident that he had broken no laws or taken any actions that were either dishonorable or dishonest.

The couple has been in the news for several months. Kitzhaber proposed to Hayes in August, but the engagement has been interrupted by the potential legal issues, as well a series of personal embarrassments. Hayes admitted to having a fraudulent marriage with an 18-year-old undocumented immigrant in 1997, who paid her $5,000 to help him gain legal status. She then admitted to purchasing a rural Washington property in the late 1990s with the hope of growing large quantities of marijuana.

Kitzhaber won the governor’s office in 1994 after rising through the state legislature. He served two terms, then made a comeback for a third term in 2010, winning an unprecedented fourth term last November, which made him the first governor in Oregon to start a fourth term. His resignation also makes him the first to resign because of alleged misconduct.