I am sorry you are going through this. No matter what anyone tells you, it is still going to sting. You have every right to be upset and angry.
As someone who had a destination wedding and had some people let me down, trust me when I say the people that are supposed to be at your wedding will be.
Sometimes old friendships change and it is time to make new ones.
I am only still good friends with a handful of people that I grew up with. People change. Some people were great "party" friends, others were great study buddies, others great shopping friends...well my life is now about my family so our best friends now are other parents with kids the same age.
Also, as someone with kids, too much stuff going on, it would be hard for me to go to a destination wedding for a friend right now. If it was a great friend, I would make it happen but it would be hard.