He says he didn’t feel the need to tell me and I don’t understand why

So around a year ago my partner quit smoking. Since then , he would have a sneaky smoke if he goes out with the boys or if he is stressed at work. He will only have one but would always tell me when he comes home.

Anyways three nights ago he bought a packet and didn’t tell me. Two days ago he said he’s going to have a smoke and I was like no you’re not you’re joking and he said he was being serious but I assumed we left it as a joke because he didn’t show me any cigarettes and didn’t try hard to prove he was being serious (we joke around all the time) . He only smoked when I was upstairs in our room sleeping, he didn’t have the packet laying around, he had it in the room that I NEVER go in but he plays his games in.

And then last night I found out he actually bought a whole packet of smokes . Apparently his first packet in a year because he “just felt like it”. I feel hurt that he didn’t tell me but he’s saying he didn’t feel like he needed to announce it.

I feel like I’ve been there with him from when he “quit” and I thought we were close enough (even on a friendship level) for him to WANT to tell me . Like it’s a bit of a milestone buying a first packet in almost a year , I just thought he would want to share that with me. But he’s saying he didn’t feel the need to tell me. So frustrating because now he is mad at me for being upset about it!

I just feel like if I had quit something and then a year later started it up again (even if it was just for the one time), he would be the first one I’d go to tell. Especially if he was the first person I told about me quitting in the first place ..

I just can’t get over this I don’t know why it’s upsetting me so much but I’m finding it so hard to get over this !