Well my husband and I are both in the military. Unless your husband is firmly set on doing his 20, maybe because hes on the high 3 plan, then okay, she will move around a lot until high school. But I moved once when I was 16 and it SUUUUCKED because it deprived me of everything I ever knew. I think a few trial runs in elementary and middle school would have done me wonders. However, we are kinda excited to give an experience to our daughter to not be afraid of leaving her hometown and exploring other places.

Now, back to the one child argument, my husband's work schedule is unpredictable and annoying devoid of federal holidays. But you know what? I don't worry because I can handle my 1 on my own AND enjoy it. I think of the days that lie ahead of us of swim, dance, soccer and how really I could make all that happen with one baby vs. Forcing my 2nd baby into dance because child 1 does the same thing (aka my childhood experience).

Idk, we've never cared to think about giving our daughter a sibling because we just simply dont want to do pregnancy and newborn stage again so we feel our one is going to have to make do. And as others have pointed out, you should have a 2nd baby if you want a 2nd baby, not to "please" your one. There are plenty of anecdotes on this sub of adult onlies who post their experiences growing up and they generally comfort me in our OAD decision.