Dinner party last night, lots of good friends and one friend with a husband I don't know very well. He smokes, I said fine, you can smoke in the back garden. He went a few times made jokes about how cold it was '...minus one degree now!!' etc etc. There is a small extra toilet, in a tiny bathroom, next to my back door. I went in this morning and the window was open and a fag butt was floating in the bowl! I felt sick. AIBU to ask him about it?