Thankyou for sharing more of where you're coming from
@Cap, and honestly, I can actually empathise with your concerns.
I have for all of my past almost 9 years have been spent focusing my attention on preaching the gospel of polygamy.
May it be that you have been too focussed on polygamy, to the neglect of the more important aspects of the Gospel? I say that not just as a criticism of you, I think the same criticism could be levelled at many of us for at least a period of our time walking with God.
It is common for people to become overly focussed on one issue, and even when that issue is itself right, the over-focus on it can become a problem. I can think right now of people over-focussed on the errors of Catholicism, on abortion, and on the world being flat, to the point where it gets in the way of them reaching others with the Gospel. Two of those issues are correct in my view, but it's not about correctness or error. All three can become too singular. Polygamy is just another issue that people get too focussed on.
Maybe God is telling you it's time to walk away from preaching polygamy, because He has other work for you to do.
But you don't need to change everything you know to be true in order to move away from it. You may just need to change your focus.
This entire discussion may actually be you continuing to debate the very distraction (polygamy) that God is trying to get you to move away from. Maybe you won't know what His actual next plan for you is until you stop trying to argue either for OR against polygamy today?
I have seen more family destruction than birth
So have I.
I see the purpose of this ministry being to promote good marriages, not promote polygamy specifically.
Our first job is to help AVOID that family destruction that we have sadly all seen. I have spent more time telling people "slow down" or "don't go there" than promoting polygamy. People promote polygamy to themselves (sex is attractive). When you've seen both successful and unsuccessful families, you know the differences and you can see the warning signs.
Our second job is to provide support for existing polygamous families - including both those that are fundamentally sound but need support with details, and those that probably shouldn't have begun in the first place but did anyway and are now in a mess they need assistance to rebuild into some semblance of positive marriage. This also includes supporting people in the fallout from unsuccessful polygamy, such as abandoned wives.
There are many people who need our support, and that is precisely because polygamy is difficult and does often result in family destruction when attempted in the modern day. Even if this ministry did not exist, men would sleep with more than one woman - they have done so throughout all generations. Our job is to meet people where they are at today (which may be monogamy, polygamy, or even a mess of interlocking relationships they struggle to describe), help them to see this situation through God's eyes, and steer them in a positive direction from this point forwards.
There are plenty of marriage ministries that believe polygamy is not valid for today. They have their place. This ministry specifically exists for those people who believe it is valid for today. This is a niche sector of Christianity that is not served by the existing marriage ministries.
Even if you, personally, shift to believing that polygamy is not for today (and you are welcome to change your mind on that), there will still be many Christians who do believe it is valid for today (even if you believe they are wrong). Some of them will get themselves in situations where they need support from a ministry that is willing to see them from a non-judgemental perspective and work with them to find God's will for their life from this day forward. This ministry exists to support these people.
If you no longer hold this view, that's absolutely fine. But if so, you may find there is little point in you working in this area of ministry, and God may have work for you elsewhere.
But, I have recently come to a situation, one I would rather not describe here, that leads me to really want to find out the practicality of polygamy in today's world.
I think you have had sufficient exposure to both positive and negative examples of polygamy that you can probably answer that question for yourself, in the context of a specific situation. It may well be that in the specific situation you have in mind, polygamy is not practical. Every specific situation is different. Obviously I can't say any more than that without knowing more of the situation.