Yea Vise I agree with OTW. I know it is tough but they are her family. I was extremely close to my wife's side. I still see them once in a while and they are very warm and friendly but they do not go out of their way to contact me nor do I expect them to. Think of it from their perspective, they are in a real tough spot themselves. I also doubt there was any serious discussion about you not going to the event. I think they are just going with the flow and letting your W call the shots like OTW says. It is just the way it is in these situations, nothing you can really do about it.
Don't beat yourself up about missing some family events. I doubt the outcome would have been much different. Don't over think things, you will never know the actual story.
