He laughed about someone being rude to me..

We took our dog to the groomer. At first this groomer refused to take us because of several reasons regarding the dog (breeder dog; she wouldn’t take breeders vacc info, etc.) She was very rude about it. We complied with everything she said and brought him in another day with an appointment. My fiancé said Goodmorning to her and she didn’t respond. When she asked what specific vaccinations he has had, I was explaining them to her while I was also looking for the actual documents on my phone. My “fiancé” said that she put her hand out and cut me off and said “I don’t need to hear all of that, I just need to see the papers”. I didn’t notice what she said or did because I was focused on finding the paperwork. After I show her the paperwork, my fiancé is standing there saying “why are you talking? Just show it to her” and “you don’t have to explain, she doesn’t want to hear that”.. like damn OK. He wouldn’t shut up about it, mind you this was AFTER I had shown her the paperwork. Then he proceeds to have a conversation, all normal, with the groomer about how our dog is super playful. Then we leave the dog with the groomer and step outside and I told him that he didn’t have to say all of that. He then says “she shut you up” and starts laughing. Saying that the groomer stuck her hand out and “shut me up”. Like why is that funny? He then starts yelling at me in the store. Like I was just so confused. So if somebody is rude to him, I should laugh at him and then yell at him about how he feels? He’s been like this lately, super rude, quick to blow up at me, insensitive, hostile. There has to be something going on with him.