I sympathise you much !
My ex- boyfriend is a sexy man and has been lot of girls wrapping.
I understand your jealous, doubt and angry feelings. But from my experiences, first of all, try to keep calm !
Keep an open mind to see exact and obvious things. You must find more evidences.
Brushtooth and slippers are not enough to go to definite what happen although there must be weird and creep here.
It deserves to dubt !
In another hand, you do try to observe meticulously all your actions and gestures of boyfriend and her(when all of you together).
But don't be plicit ! Only observe them discreetly.
Good luck !