I am really surprised by a couple of things. I would never expect anyone to pull their kid out of school for a WEEK for a wedding and I wouldn't expect anyone, even close family to go to a lot of expense to attend a wedding. My husband's brother and his family didn't make it to our wedding - they had three small kids in school and it would've been expensive for the five of them to travel all this way. His grandparents didn't want to fly. My own best friend was in finals in nursing school and couldn't make it. My husband was there, we got married, that's the important part. I missed my brother's wedding (I was in NY, he was in La) because we were moving on the same weekend they planned our wedding. We didn't have the time (limited vacation days) or the money (first month, last month, deposit in NYC, plus moving expenses = all the money we had in the world). My brother understood. No one was mad.
So to the OP, all your reasons are perfectly valid. Your husband is going. Anyone who is going to be huffy with you over not wanting to spend a fortune or pull your kid out of school for a week? Is being unreasonable.