A nurse invited a teenage colleague to 'fill in' the gap while he could not sleep with his pregnant wife, a disciplinary heard.
Noah Kantoh, 35, made the sexually motivated comment to the 17-year-old cleaner while working with her at the Medway Maritime Hospital in Gillingham, Kent.
He had been accused of a string of charges against her, including trying to kiss her, groping her breasts and accusing her of spurning his advances because he was black.
But a Nursing and Midwifery Council panel found there was insufficient evidence to support the bulk of the charges against him.
However, the lone remark Mr Kantoh was found to have made - "You can fill in the three-month gap as I can't sleep with my wife" - amounted to misconduct and meant that his fitness to practise was impaired.
Imposing a three-year caution order, panel chair Laurence Peterken said: "The panel accepts this was an isolated incident involving a colleague and patient safety was not compromised.
"The panel accepts that your conduct, albeit serious, is on the lower end of the spectrum of sexually motivated conduct.
"Although you have shown insight, you have not shown full insight and there was no admission to any of the facts proved."
He added that in directing the caution, he wanted the panel to make clear that Kantoh's behaviour was "unacceptable and must not be repeated again".
A further charge relating to a clinical error while dispensing medication was also found proved, but the panel ruled it did not amount to misconduct.
The cleaner, now in her early 20s, said she had made it clear to Kantoh that she was not interested and that his comments, made between October 2007 and October 2008, "disgusted" her.
But defence witness Peterkin Ofori, who worked with the pair at the hospital, said they knew one another well and were on "friendly" terms.
He said the girl had told him she had been 'bullied' into reporting Kantoh, but would not confirm by whom.
"I called her straight away to find out had happened. I was shocked," he explained.
"She then told me she was bullied to make the allegation. I said by who but she would not say. She did not want to talk about it.'
Mr Ofori also confessed to having an affair with the girl in June 2008 and said he had heard rumours that there had been other relationships as well.
The panel also found that while working at the Fountains Nursing Home in Manchester Kantoh had dispensed medication from residents' blister packs and placed them into pots on the trolley, contrary to the home's policy on March 24, 2010.
