I'll say the same thing but from a different angle. I've missed a lot of my immediate family events due to four deployments and nearly all of extended families' events - and they missed my kids' events mostly due to finances and distances to where we were stationed.
We've learned for most things it's just a day and this summer we chose to skip a family event because the burden would just be too high considering all the moving pieces.
You need to set criteria on what needs to be celebrated that day and what can wait or be celebrated from afar. We've learned most things are just a day on a calendar. We celebrate birthdays before or after a deployment. Ditto anniversaries. Graduations can be recorded and unless the family member is speaking as an honor grad, it's not worth traveling across the country.
Weddings are a big deal and worth scheduling around the best you can but it's fair way in advance to say this month doesn't work for me. Family is very important to me, both my immediate family (kids are teens) and extended but life has taught us to be flexible and simply enjoy the times we have, whatever the date written on the calendar.
Medical issues need to be prioritized. I wasn't able to go home from deployment when my dad has a quadruple bypass. I really wish I could have, and would have made it happen if not deployed. Thankfully, all went well. At the same time, my dad or sister have had less life threatening surgeries that I have no guilt not traveling across the country to be there.
I've struggled with boundaries myself and can't say if you are setting improper boundaries because that is both a personal decision and we have a paragraph of facts. That said, I recommend Henry Cloud's book "Boundaries: When to say yes and when to say no to take control of your life."