The looks of pity are only going to come depending on how you carry yourself, and what you put out there.
After all, you are not being left at the altar, or having your fiance cancel your wedding.
You are the one who made an executive decision, which will preserve your quality of life for years to come.
That is something to be proud of.
If people ask, you can offer a postponement statement.
You dont owe anyone anything, but if they were going to come, or to avoid the shower type of thing, you might consider starting to make statements about postponement.
Why, how, or whatever is none of their business.
A statement like,
"We are just not going to be able to do it this year...Had to postpone... family issue..."
You could even call it a family health issue. That would not be a lie, either.
I know it must be hard, but try to at least secretly be proud of your strength.
Many lives have been ruined, Im sure, by people going through with weddings under duress.
I am inspired by your strength and conviction.