Your kids and spouse can travel to visit family as often as you want to pay for it (assuming your spouse doesn't work outside the home or need to arrange vacation time). When we lived in Japan, it wasn't at all uncommon for some families to decamp and head to the States for a month during the summer deployment schedule. (I won't say "travel home", because to me, home is wherever my spouse and I live, and I think calling something else "home" isn't good or helpful for anyone.)
As for not being around family, meh. I was an Air Force kid. We never lived near my grandparents, aunts and uncles, cousins, or anyone else. It didn't bother me because no one suggested to me it was wrong or problematic. Those people were like Santa Claus--these amazing people who I didn't see often, but it was all the more special precisely because I didn't see them all the time. To me, that's what grandparents were.
Also, I have relationships with people who are like family to me and that's delightful. This goes back to when I was a kid. Recently, the daughter of someone my parents were stationed with and very friendly with traveled briefly through a city near where my sister lived. We haven't seen these people in probably 35 years, but my sister and I have fond memories of the parents and kids. Their daughter reached out to my sister to get together while she was passing through.
I've celebrated a friend's kids birthday with their family, when we all met in South Africa while we were living in Japan and them in Bahrain. Were those kids sad they didn't have grandma to hug on the birthday? Or thrilled that they were petting a zebra in the backyard of our airbnb? You make sacrifices, but you get some pretty cool shit in return. And that goes for the whole family.
I share that to show you that even if you don't live near blood relatives, your wife and future kids will make connections. I've had Thanksgiving at the home of friends when my spouse was deployed because they were thoughtful enough to include me. My parents included in their Thanksgiving the wife of someone from my husband's command whose spouse was deployed. It may not look like a traditional holiday experience, but it's still pretty cool.
So what to expect? Expect that you will miss holidays with family, and/or celebrate them a week before or after the actual day, when that's the holiday leave block you can get. Yes, that will happen. And you'll miss anniversaries and birthdays (maybe even births) and spelling bees and soccer championships. It's gonna happen sometimes. But also, you will see the magic of Tokyo at Christmas, or fly to Barcelona for Christmas, or spend Christmas in London with friends you know from being stationed in Japan, who live in the Netherlands while you live in Germany, and you meet up with them and their 4 kids in England for the holiday. Is that better or worse than sitting in the family matriarch's living room somewhere in Texas where the kids have been dozens of times, opening gifts? Only you can decide that, but for your kids, the way you frame it will be reality, so just don't talk about it or let your extended family talk about it like it is deprivation or anything negative.
If you focus on being away from "home" and family, you are missing the point. The connections we've made during my husband's Navy time are incredibly special. The connections my family made when I was a kid, during my dad's service, are incredibly special, too. You'll give up some time with extended family (and non-extended family), but you may just find that what you get in exchange is even better. Only you can decide if you want the Norman Rockwell life of every holiday surrounded by cousins and aunts and uncles, or if Thanksgiving turkey for you can happily mean Thanksgiving *in* Turkey while you live in Europe.
