The father of missing Claudia Lawrence has spoken of the "daily rollercoaster" experienced by him and his family in the year since her disappearance.
Peter Lawrence, who has spearheaded a campaign to keep his daughter's name in the public eye, told BBC News he believed his daughter was still alive.
He issued a further plea for help in tracing the York chef, saying while she was missing a part of his life was too.
Police are treating Ms Lawrence's disappearance as suspected murder.
"It's a daily rollercoaster," Mr Lawrence said. "We sometimes stop and think: 'Where on earth are we, what's happened and how did it happen?'"
Referring to the police investigation, Mr Lawrence said: "I think it is going extremely slowly and painstakingly."
She just disappeared into thin air
He added that it had been difficult for the police from the beginning of the inquiry, and said he still had faith with the way the investigation was being handled.
"The police only came into this the day afterwards," he said. "There's no starting point from there. She just disappeared into thin air.
Addressing reports about his daughter's personal relationship, which has been one focus of the inquiry, Mr Lawrence said he had been dismayed by one or two "more lurid" allegations about her love life.
"She's had something like 12 relationships with men of one sort or another over a period of five years," Mr Lawrence said.
"For a 35-year-old single girl? I think a lot of people would have had a lot more."
Mr Lawrence said it was a possibility that the jealous partner of one of the men his daughter may have had a past relationship with with could be responsible for her disappearance.
He said the support of family and friends, his community and his work as a solicitor had kept him going over the past 12 months.
Mr Lawrence said he believed it was likely his daughter had been taken by someone she knew, and that she was still alive.
"How anybody can disappear off a street in a residential area in a nice part of York, I just don't know," he added.
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