Hi watchmeimflying - i would bring this matter up as soon as you feel able too. You need to explain that you're in a situation where you require mutual trust and that you feel unnerved by what you saw. I wouldn't openly accuse him or demand an explanation. To be perfectly honest he could well have been in an emergency situation and then on the way home quickly did some shopping. Or he could genuinely have forgot and saved himself the embarrassment by lying to you instead. You'll probably never know know so questioning him further is rather pointless. Instead of focusing too much on the actual events i would discuss how you will move on from the situation i.e. you would like a more open relationship and that you understand if he forgot and its ok for him to tell you so in the future. He probably doesn't want you to feel unimportant to him. The issue will only fester so if you can't talk to him openly maybe leave a message or write him a note? I hope this situation resolves positively for you. All the best.