I just moved it.
I completely agree with Andrew. If YHWH intends for this to happen, He will make it happen, in His timing and with the person He has in mind. I'm not saying not to look at all, obviously we have to have our eyes open enough to be able to see whoever He brings along. However this should not be a key focus in our lives.
And in all probability the woman He has in mind for you won't be on any polygamy-focussed website anyway as she won't even realise it is an option.
You are most likely to come to know her in real life, through a route you never expected, and at a time you were not expecting either.
The best way to find her (if YHWH even intends this for your lives) is to give up, pray, and give your entire lives to YHWH to do with as He will. Stop focussing on finding a woman, instead focus on YHWH. Find whatever His next step for you is, in any area of your life, and do that. Then ask for the next step. You'll never know the destination, just the next step, and the road you end up travelling will be both more challenging and more rewarding than anything you could have worked out for yourselves. And if she is to be in your lives, she'll be somewhere along that road.