My GF(32F) is mad at me (30M) for being honest

me (30M) and my girlfriend (32F) (2 year relationship) are arguing currently. we both don't like dogs on our bed, but we were watching a friend's this weekend.

while i was out, she was on the bed and the dog hopped on and laid on my side because she was "too lazy to get him off". i didn't know this until i went to go to sleep last night and there was dog hair on the bed. There was also an odd stain on my blanket.

i texted her and asked if the dog had been on the bed. she said yes. i switched the blanket out. i then asked if he had been on there for just a second or a while and she said a while. i didn't reply.

i was annoyed and a little grumpy in the morning but moved past it within a couple minutes. however, when doing our weekly relationship check-in today she asked "are there any small things that bothered you that you haven’t discussed with me?". i told her that the dog on the bed had bothered me a little. she got upset, and she was curious why it bothered me "so much" and was annoyed that i got upset about it in the first place. i said it wasn't a big deal, but i was just answering the question she asked. i told her "you probably wouldn't like it if the dog was on your side", which made her more angry. she said "the more you want me to apologize the less i want to". i told her she needed to do some digging into why that is. now we aren't talking.

just venting and looking for some advice i guess. i feel like this has become a pattern and i dont really know what to do. TIA