Alarm bells began to ring in August, when a number of males who she didn't recognise were calling to her address in order to have sex with the vulnerable young woman.
The woman, who cannot be named for legal reasons, has a history of sexual exploitation.
From the age of nine, she ran away from home on 10 separate occasions and it is believed she been subject to "sexual violations and rapes."
Court papers obtained by The Times newspaper state that "significant concerns arose that (she) had been subjected to sexual activity with men". This included "sexual violations and rapes" while she was still a child.
When she became a teenager, she developed an "obsessional interest" in men, particularly "from different ethnic or cultural backgrounds".
Manchester City Council has been in charge of the woman since 2015 and it employed a specialist company to provide her with 24-hour support.
However, that same year, she met a restaurant waiter of Bangladeshi nationality and the pair married in 2016.
Despite this, just 12 months ago she is understood to have embarked on a series of risky attempts to have sex with men she barely knew. She also sent them dozens of nude photographs of herself.
Because of this, Manchester City Council told the court a psychologist employed by the company believed giving her "unsupervised contact with men" was in her best interests.
In a statement, the UK's The National Autistic Society said "urgent lessons" should be drawn from the case.
A spokesman said that while autistic people have a right to a sex life, "the responsibility to keep people safe falls on those in positions of care, like the courts, councils and support providers" and that "its essential safeguarding measures are followed meticulously".
Lucy Powell, the MP for Manchester Central said: "This is an appalling case which raises serious questions about the care system for vulnerable adults. The decision by the judge and care provider, against the wishes of the local authority charged with this woman's care, beggars belief."
Manchester City Council said it took the case to court to help figure out how to deal with the young woman's behaviour.
"Various parties have had to weigh the young woman's freedom against the need for restrictions in the interests of her safety. Our priority has been to keep her safe from harm, acting in her best interests," a spokesman for the council said in a statement.
"We took the case back to the court in September precisely because the situation which arose was so concerning and we felt it needed to stop to protect her from harm."
