Here are my two cents..
I think every once in a while you have to take one for the team even if it's not technically your team...
My SIL is on bed rest for a pregnancy and asked before this if she could "use" my house and yard to have a birthday party for her DD 3. I was hesitant at first because reality is DH and I will foot the bill and have to do the work and this was prior to her being on bed rest. She and BF will bring some stuff, but trust me when I say, DH and I will do the work and foot the bill including picking them up and bringing them to our house since they don't have a car.
Now she is on bed rest and I think she should cancel the party. In her and BF's mind theyt should still have it which of course will absolutely mean work and expense to DH and me.
Even though I want to cancel the party, I won't. Even though I want to sit there and not help, I won't. Even though I want to not buy decorations and balloons etc, I will. Why, because at the end of the day I love my husband and will do this for him with a smile.
As far as missing weddings. I did not attend my sister's wedding at Sandals because I was not comfortable leaving DS at home for 4 days. I felt really badly, but I took a couple days off, stayed home with my brother and other sister's kids and the following weekend DH and I rented a tent, tables and chairs and threw them a reception, in our back yard for family and friends. Not a mega event, but probably spent around $1000.
DH didn't blink about our spending this or doing alot of work because at the end of the day, he loves me and he did it for me.
I also threw baby showers and cristening parties for both of my sisters in law.
Again, simply because I love my husband and when we married his family became mine and mine his. That, I think are the opinions of those who don't really agree with your lack of participation and attitude about the weddings.
And FTR, you should absolutely go on vacation just your family. Everyone in our families know they are not invited on our DW trips.