Philpott fire deaths trial shines light on polyamory
Mick and Mairead Philpott shared their home with Mick's girlfriend and 11 children in a relationship which can be described as polyamorous.
Why do people live with more than one sexual partner, and are there problems that can arise with these relationships?
Mairead Philpott said she was initially hurt by her husband's relationship with Lisa Willis, but went along with it because she was scared of losing her family and home.
While there is little research on polyamory, research on polygamy - where people marry multiple partners - suggests that some women can feel pressured into consenting.
Dr Thom Brooks, who has researched polygamy and polyamory, said a lack of consent by women was one of the most significant problems.
"The two are practised very similarly and [are] almost always a relationship of one man with two or three women, with the man at its centre," said Dr Brooks, of Durham University.
But marriage and family therapist Dossie Easton, who has been in polyamorous relationships, said they were different in nature to polygamous marriages.
"Polyamory does not follow the rather strict forms of marriage and gender in relationships that are found in many polygamous cultures, [such] as in Islam and Mormon[ism]," she said.
It is difficult to estimate how many people in the UK are polyamorous, as some keep their relationships a secret.
But Ms Easton believes more people are experimenting as polyamory becomes less frowned upon, in the same way that same-sex relationships are now widely accepted.
"Polyamory has come out of the closet, and thus more people feel free to try what had been very forbidden," she said.
"Nowadays you don't have to be a hippy or a rebel to explore an expanded sex life."
She added that people who "insist on judging other people's relationships" are "unacceptable".
An appearance on ITV's Jeremy Kyle Show, in which the Philpotts outlined their living arrangements, led to death threats and bullying of their children.
Dr Brooks said the reaction of family, friends and wider society could cause social stresses for people in polyamorous relationships.
Mick Philpott was unemployed but the family still revolved around him.
His wife and mistress both worked but their wages and benefits were paid into his bank accounts. Trial witnesses said his wife did the majority of the household chores and childcare.
Dr Brooks argues that polyamorous and polygamous relationships subordinate women.
"Their practice privileges the position of men over women where the family revolves around the man at its head surrounded by his largely dependent family," he said.
"In practice, it is often the men who choose who joins."
So why are men more likely to have multiple partners, rather than women?
"The religious and legal reasons are perhaps well known, but others are more speculative," said Dr Brooks.
"One argument is that men are perhaps more prone to jealousy and less able to share a wife with another man, but I have not seen much evidence to support it."
In their evidence, Mairead Philpott and Lisa Willis agreed that they became like sisters over time and they considered each other's children to be their own.
Ms Easton's experiences of polyamory are similar.
"We banded together to raise our children and formed large extended families... relationships could be closer, or more distant, or even hostile, and are still family," she said.
"Children in these families grow up with a rich supply of aunts and uncles, and cousins and siblings, and thus benefit."
'Disease and violence'
Dr Brooks has looked at research which suggests women in polygamous marriages are at a greater risk of harmful effects, including sexual diseases and family violence.
"The primary mental and psychological problems for women are perhaps depression. For example, where one wife becomes pregnant her husband may become more likely to take an interest in his other wives," he said.
The women can also be powerless, he argued, because they are typically less educated and lacking in employability skills.
"I should emphasise that polygamy has also been linked with harmful effects on men, too," said Dr Brooks.
"They also tend to be less well educated and suffer from depression, perhaps as a result of the additional stress of having to provide for a larger family."
Ms Easton said jealously was common in polyamorous relationships, but "only a few find it to be an overwhelming obstacle".
"Our culture virtually demands jealousy as proof of love, so some relearning is usually needed," she said.
So provided all partners consent, is there a problem with polyamorous relationships?
Ms Easton doesn't think so.
"Poly people learn to manage jealousy and take care of themselves and their partners and their partners' partners when they feel jealous," she said.
"A lot of very healthy emotional growth can happen in this healing process."
But Dr Brooks still has concerns.
"The problem remains that both polygamy and polyamory are more likely, in practice, to privilege men over women in structurally unequal relationships," he said.
"Those of us concerned about the reproduction of inequalities will have some difficulty supporting either polygamy or polyamory."