Czech Prime Minister Petr Necas who said he was stepping down Sunday survived eight gruelling confidence motions before an alleged love affair gone wrong ended his career a year before scheduled elections.

The bespectacled 48-year-old physicist, in office since July 2010, paid dearly for trusting Jana Nagyova, his chief of staff -- and alleged lover -- who was indicted Friday for bribery and complicity in abuse of power.

Police said she had asked military spies to tail Necas's wife, Radka.

Necas announced earlier this week the marriage was over after was 25 years.

The staunch fiscal hawk is perceived as short on charisma. He has led a faltering coalition of three centre-right parties which saw its once-strong parliamentary majority gobbled up by graft scandals and party infighting that gradually reduced its popularity.

Ironically, Necas had made a high-profile anti-corruption drive a centrepiece of his administration.

"A police raid as a full stop to Necas's career as prime minister would be an incredible paradox," the Lidove noviny broadsheet said in a commentary on Friday as the graft scandal that led to his resignation erupted.

The charges against Nagyova followed unprecedented police raids last week on the cabinet office, defence ministry, villas and a bank.

Necas on Sunday also stepped down as chairman of the right-wing Civic Democrats (ODS).

He was first elected to parliament in 1992 and steadily climbed the party ranks until he became prime minister three years ago.

With the reputation of the ODS hit hard by numerous corruption scandals, Necas's "Mr Clean" image bolstered his leadership role in the party -- until the events of this week.

Notoriously prone to high levels of corruption, the Czech Republic ranked behind countries like Costa Rica and Rwanda in Transparency International's 2012 Corruption Perception Index.

As minister of labour and social affairs in 2006-2009, Necas kicked off reforms to the pension system viewed as key to ensuring long-term sustainability of the country's public finances.

His government approved further reforms to the pension system while bent on an austerity programme which won him the general election in 2010.

But recently Necas gave up on his austerity drive. He insisted that supporting economic growth was the key as the eurozone crisis suffocated the Czech export-oriented economy, sending it into its longest recession ever, lasting six quarters in a row.

While Necas has been a member of the rightist Civic Democrats since their creation in 1991, his rise to its top was slow but steady.

Born on November 19, 1964, in Uherske Hradiste, about 300 kilometres (225 miles) southeast of Prague, Necas earned a degree in physics from Purkyne University in Brno.

He went to work as a research and development expert at electronics maker Tesla Roznov in the east of the country before starting his career in politics.

Necas has four children with his wife Radka -- two sons and two daughters -- and has been careful to guard his family's privacy.

In addition to reading and music, he enjoys skiing and cycling -- "an important activity, given the sedentary political occupation," he once said.