Bit of background: DP used to be a smoker, it helped him cope with a high stress degree at uni and then the high stress job it then led to. He quit smoking before he met me and stuck to vaping to help wean him off smoking completely. I have wanted him to quit full stop for a while and he knows this. I recently moved in with him and he adamantly told me he'd quit both smoking and vaping. Fast forward to three weeks later and I was folding a pair of his jeans to put away whilst he was working from home and a small vape refill fell out of his pocket. I confronted him and he told me he hadn't actually quit vaping at all and had been doing it behind my back (whilst commuting to and from work, whilst popping out to buy a paper in the mornings etc etc) He said he was going to tell me but kept putting it off. I told him I wasn't upset about the fact he was vaping ( he's a grown man, he can do as he likes) I was very much upset about the fact he had repeatedly lied to my face. He's now moping around the house feeling sorry for himself. AIBU to be supremely pissed off at him?