I hope you find your way to love and clarity.
My advice, if you are seeking advice here:
THIS IS ABSOLUTELY NOT THE TIME YOU PROBABLY SHOULD BE DEALING WITH THESE ISSUES.
I had post-partum depression until my son was nearly three. I was nearly hospitalizated. The cures were medication, going back to work, therapy, and time.
I could be wrong!!! I don't know what state your wife is in. Again, might be wrong.
But after the birth of my child, I felt wholly terror. I could barely function. It would be absolutely the worst time in my life to discuss being poly or opening up or even dealing with my sexuality (I have sexual issues too). I had NO strength and spent every day trying to survive emotionally.
And you and your wife have a tons of other kids to wrestle with?
Does she work out of the home? If not, she may also feel isolated. I don't know you, and I''m just trying to send you some empathy. But if your wife is emotionally tender or has post-partum - this would, in my opinion, be the worse time to decide anything! Moving. Being poly. Anything. What's the rush?
Why not let her heal and get the kids to age a little? Now, my son is 11 and it's a heck of a lot easier to focus on my relationship and what I want. I think you are asking way, way too much of your wife at this point in her life!