Tim Farron's leadership has been dealt a blow after the Lib Dem peer Lord Paddick resigned as the party's home affairs spokesman citing concerns about the MP's views.
The Lib Dems gained three seats in last week's election, but had a hard campaign marred by repeated spats over Tim Farron's views on homosexuality.
"The consequences of the focus on my faith is that I have found myself torn between living as a faithful Christian and serving as a political leader", he said.
Asked why his answer had changed, he said: "I'm quite careful about how I talk about my faith. Sometimes my answers could have been wiser".
The BBC's chief political correspondent Vicki Young said Mr Farron had spoken at length at the "personal quandary" he found himself in and how he felt questions about his faith had "distracted" from the party's efforts during the election.
"And to live as a committed Christian, to hold faithfully to the Bible's teaching, has felt impossible for me", he said.
"Even so, I seem to have been the subject of suspicion because of what I believe, and who my faith is in".
Former business secretary Sir Vince Cable and his fellow coalition minister Jo Swinson, who both returned to the House of Commons this month, are among the favourites to replace Mr Farron as party leader. If there is more than one candidate, the position will be decided through a secret ballot after a hustings on June 27 or a single appointment will be made on June 20.
"When I get asked theological questions, which I don't think many other politicians do get asked, I took the view that it would be better for me to say this is a matter of theological nitpicking, and let's talk about the politics".
In a Q&A with PinkNews before the election, Mr Farron said: "I am a proud advocate of LGBT equality and have a track record that demonstrates that".
Despite the setbacks, the Lib Dems went on to add four more seats in last week's polls, increasing their number of MPs to 12.
The Lancastrian took over from Nick Clegg after the 2015 election, which saw the Lib Dems suffer near-total wipeout after being in government with the Conservatives for the previous five years.