Dallin H. Oaks states "I don't know" about eternal polygamy.
"Elder Oaks Interview Transcript from PBS Documentary," LDS Church Newsroom (July 20, 2007), accessed Sept. 13, 2021
HW: There still is some confusion that polygamy is definitively and unequivocally disallowed in this world. What will happen in the next? There is a perception that polygamy is part of the afterlife. Could you talk a little about that?
DHO: If I talked about that I’d be making doctrinal statements where the prophet has not chosen to make doctrinal statements, so I think I shouldn’t say anything except to affirm that a lot of people, myself included, are in multiple-marriage situations. Look at the significance of that. There are a lot of people that live on this earth that have been married to more than one person. Sometimes those marriages have ended with death; sometimes they’ve ended with divorce. What does the next life mean to them in relation to a covenant they once made and so on? I don’t think those people have much of an answer for that question. It might not bother them because they don’t believe that people will live as married couples in the next life. And if they don’t make and live for the covenants to do that, [as for themselves] they’re right! But for people who live in the belief, as I do, that marriage relations can be for eternity, then you must say, “What will life be in the next life, when you’re married to more than one wife for eternity?” I have to say I don’t know. But I know that I’ve made those covenants, and I believe if I am true to the covenants that the blessing that’s anticipated here will be realized in the next life. How? Why, I don’t know.