Sylvester Mwendwa and Elijah Kimani from Kisimani in Kisauni, Mombasa County, signed a written contract last week after realising they have both been having an affair with the same woman for more than four years.
According to the contract, the men will take turns to stay with the woman, who is a widow with two kids. They also agreed to respect one another and raise her children.
The trio is aged between 25 and 31, said community policing officer Adhalah Abdulrahman who came to know of the issue during a fight, Kenyan newspaper 'The Daily Nation' reported.
When asked to make a choice, the woman - who does not wish to be identified - also declined, saying she could not live without either of the men. This made the men agree to take turns to live with her.
More From This Section
Mwendwa claimed he went to the woman's parents and was given permission to live with her and pay bride price when he was ready.
While polygamy - one man having more than one wife - is legal in Kenya and widely practised by various communities, polyandry - one woman having more than one husband - is almost unheard of.
Lawyers said the two men would have to prove that it has been part of their custom to practise polyandry, otherwise the union would not stand.
A family lawyer, Judy Thongori, told the paper that polyandry is more abnormal than illegal since the laws that govern marriage in Kenya do not clearly forbid it.