The ideal way
My wives introduced me to other women that they chose. A few that they chose were cool to the idea of sharing, a couple of others didn't work out at all, but the ladies picked well generally. J and M have talked about adding another woman to our family, but while I'm sure they would choose well, I'm perfectly happy the way things are.
I try to love my wives this way, unconditionally! Husbands love your wives, even as Christ loved the church, and gave himself up for her. Eph. 5:25