'If he hadn't wanted more wives, I probably wouldn't have married him': How women are the driving force behind polygamous marriage

From an outsider's perspective, a man who can convince more than one woman to be married to him at any given time, clearly wears the trousers.

But a new documentary has revealed that it is actually the women instigating polygamous marriage in Mormon communities.

In the newest series of OWN's Our America, two 'sister wives', from Centennial Park, Arizona, describe how they chose their man, rather than the other way around.

Plural marriage: Isaiah (right), 28, from Centennial Park, Arizona, with his two wives Marlene, 28 (left), and Becca, 20 (centre)

Becca, 20, who has been married to Isaiah, 28, for a year and a half, told how she knew he was the one when she spotted him at church.

She told host Lisa Ling: 'One day I was in church, and I was sitting with my sister Sharon, and I saw him walk through the door. 

'I had a feeling just come over me and I turned to Sharon and I said, yeah, that's who I feel like I belong to.'

Father figure: Isaiah already has four children with his two wives, and a fifth on the way

This was despite the fact that Isaiah had already been married to Marlene, also 28, for eight years already.

Today, Marlene and Becca describe themselves as being married to each other, in the same way that they are married to Isaiah.

And for Marlene, who is just weeks from giving birth to her fourth child, she never imagined marriage any other way.

'If Isaiah had told me that he didn't want this before we got married, I probably wouldn't have married him,' she said.

She says that she and Becca, after some initial teething problems, are 'inseparable'.

'I have, right now, my best friend living with me,' she said. 'I can talk to her about any of my problems. She completely understands because she's married to the same guy.'

Becca, who is now mother to a six-week-old daughter, added: 'I talk to her every day - I probably talk to her more than I talk to Isaiah.'

Inseparable: Becca (left) and Marlene are best friends, and describe themselves as being married to each other, in the same way that they are married to Isaiah

Both plan to have many more children, and raise them together.

Marlene explained: 'We didn't want, "This is my child, this is your child". We wanted all of our kids to be raised together, you know, I'm mom, she's mom...

'I grew up with 25 brothers and sisters, and I loved it, and I want that for my kids.' 

Speaking on GMA this morning, Lisa Ling explained how powerful Mormon women actually are in instigating plural marriage.

She told how a woman approaches the community's spiritual elders when she 'receives a sign from God' about the man she is supposed to marry.

Young love: Marlene and Isaiah married when they were just 18. When Becca married into the family nine years later, she was only 19

She said: 'In this community it's actually the women who dictate who they're going to marry... They believe that at a certain point in their lives, and they don't know when it's going to happen, God will speak to them, and they will know instantly as soon as they see the man.

'The man is completely unaware - when the spiritual elders call them in, they may not even know who the girl is.'

The Church of Latter Day Saints teaches that Jesus was a polygamist, and many people living in Mormon communities, which typically shun media attention, know life no other way.

As Marlene said on Our America: 'I believe that this is the way God lives. And I believe that this is a superior way to live.'