Help! What is going on?

My fiancé and I are off work for the 4th, so we slept in. I was up before him so I woke him up in a way he’d like , etc. we had a good morning, and a good date night last night. He wanted to go running, so he took his dog with him. We have a puppy too but she’s too young still so I stayed home with the puppy to get some laundry and chores done so we could have the rest of the day free. He told me he was leaving his keys home, so I said ok just leave the door unlocked since I’m here anyways. After he left, the puppy was way too excited and energetic, and I could barely get any chores done without her getting into something, so I took her for a quick walk around the block bc that still tires her out. I figured we’d be back before my fiancé so I locked the door, we were only gone for 10 minutes. My fiancé ended up getting back maybe a minute before me and called. I told him sorry, we were one house away and I’d be right there, I didn’t know he’d be back so soon. He was pissed on the phone, cutting me off, telling me to run back, his dog needed water, he left the door unlocked for a reason, etc. I didn’t know where this attitude was coming from but I just hung up and walked over to him and handed him the keys (seriously, he only waiting maybe a minute and a half including the phone cal time, maybe less).

Once I handed him the keys he was still so rude. I tried apologizing again, I really didn’t know he’d be back so soon and didn’t mean to lock him out, but he kept going on about how it’s stupid that he was locked out of his own house. I was hurt but figured maybe he was just thirsty or something happened so I just went inside with the puppy, started prepping for some yard work I needed to do. A few minutes later I walk into the room where he’s sitting and he’s scrolling through his phone. I ask him lightly what he’s doing, he said “nothing”. Then I see he’s typing something. I was confused and was like, “who are you texting?” And he said again, “nobody, I’m not doing anything.” I started to want away but this really bothers me. Ever since I came back home, he wouldn’t even look at me. So I asked him about it. He told me to drop it. At this point I started crying, I couldn’t help it. I was like, “I don’t know why you’re treating me like this, it was an accident locking you out. Now you’re hiding what you’re doing and you won’t even look at me.” He told me I’m overreacting and to drop it, again. I asked him to just look at me and I would. He put his freaking hand up to “shield” his eyes from me and told me to drop it again.

Like wtf? I was fed up at this point. I told him he was acting so immature and I didn’t deserve to be treated like this, and I honestly had no clue where this attitude came from or why. He still wouldn’t say anything. I asked him if there was someone else . He flipped out, saying “wtf no! Why would you even thing that! Just let it go” and still wouldn’t look at me. I asked him to look at me again and he wouldn’t .

I took the puppy and left, telling him I hoped whatever this was going as worth it. I just took her to the park, I didn’t want to fight especially when I had no clue what was going on and felt like I was talking to a brick wall. I hoped some time and space to calm down would help him but now he’s ignoring my texts and calls.

Am I missing something? Like maybe I wasn’t understanding enough about accidentally locking him out, but we’d been having a good morning before this and haven’t fought much at all recently. Help!