I don't want my my aunt and her husband at my graduation
Why don't you want them there?
You don't know them, they were drunk and my uncle kept touching me inappropriately at another event. I don't want them at my graduation.
If your uncle is like that and touches you inappropriately, you have every right not to invite him or your aunt. That's horrible and you shouldn't put up with that.
I'm sort of scared of them.
They are people you have every right to not invite if they act like that.