Should i say something?

Me and my bf have been together for a while now and are thinking about getting married....we are expecting a beautiful baby girl are ao excited about it! Ever since we met I have told him that I hate drugs and that I wouldnt want to be with someone who does drugs or that has ever even tried them and he agreed and said he thought the same way and that altho he knows ppl who does them (as so do I) it doesn't mean he has ever tried them or will like to..well now to the bottom line. Today he asked me to look for a video he had aved on his phone so as I was looking for the video he asked me to look for I clicked on one and it was a video of him and his friends smoking weed idk if he forgot it was there or wat but I'm really disappointed and hurt that he lied what should I do?