What do I apologize for here?

My partner wants the best for me and to help me not let my anxiety have control over me. The thing I can't tell is if he is taking it too seriously or if I am acting poorly. Today after I left costco I realized the milk I bought was leaking. I told my partner I was anxious because the milk was leaking and I didn't notice because of a video I was listening to and needed to sit and calm down. My partner told me that I could calm down right now even but that I'm not and that I will need to return the milk. I set the milk down and put the receipt through the handle I asked him if he could go so I could sit and calm down since it would be faster. He said he thinks I should go and complete my task. I sit in the car and he tells me that I'm being childish. We get into an argument and he is raising his voice at me, so I tell him I am leaving this awful environment and am returning the fucking milk. When I get back we don't say anything for a minute. Then he tells me to check my phone. It says that I don't need to sit to breathe and that I'm blaming him instead of taking ownership of my emotions and "don't you dare think about getting back into this care without an apology on this". And so I left the fucking car and told him I'm walking home (maybe 30 min walk). He pulls up next to me and asks me to get in, I do. He starts saying how I start this shit all the time and act like a child. We argue and yell back and forth. I cover my ears and say shut the fuck up. He argues back. I keep repeating shut the fuck up after he says shit. He puts his hand over my mouth and I bite him through my mask and it leaves a mark a couple of mm wide. We yell and argue more and I leave the car and slam the door and start walking home again. He calls me again and again, saying that I need to apologize, take ownership of my feelings and that I'm yelling. We argued a bit, and I told him to pick me up and gave my location when he brought up groceries needing to be brought in. He picked me up and we didn't say anything, he just held out his hand with the now purple mark on it. We just brought the groceries in and still haven't talked to each other. He called and said he was downstairs and said something else I couldn't hear but sounded saddned. What is your take? Did I start something? How can he better help me with my anxiety? What would be better language to use?