ADVICE?? :(

So my boyfriend and I have been together almost a year. We live together. Our relationship is almost perfect. He used to vape and he quit as oer my request once we moved in together and started trying for a baby. I just found out he has been vaping and hid it from me within the last week..... I brought it up to him that it hurts more that he was lying to me more so than him smoking (even though that sucks too) I said I feel like I failed him because he couldn't trust me enough to talk to me or that he was struggling.... what should I do or say???