Heaton provides a summary of various Latter-day Saint statistics; estimates that temple sealings have a divorce rate of 25-30%.
Tim Heaton, "Dealing with Demographics," 2002 FAIR Conference, accessed November 15, 2021
Q: What about differences in divorce of temple vs. non-temple marriages?
I get asked that question more than any other I think. The national surveys don’t ask about temple marriage, so it’s hard to say. What we can look at instead is church attendance. So, for couples where the husband and the wife both attend church regularly, by the way it’s true nationally: If both attend church the divorce rate is lower; if neither attend Church, it’s higher; and if one attends Church and the other one doesn’t, it’s even higher. So having similarity helps some. So if we put together a series of guesses about an LDS husband and wife who both attend church regularly, the lifetime divorce rate may be around 25% to 30%. I would guess the temple divorce rate is in that range. It’s pretty high, but it’s still a lot lower than the national 50% rate. Somebody asked about birth rates. Mormons have more kids; their ideal family size is about one child more, and they expect to have about one child more, than is true nationally, depending on which survey. So yeah, higher fertility rates.