<human>: Can you succinctly summarize the text in 1-3 sentences?

It's something little and pithy, but I always worry it's going to blow up some day.  This is the first time he's really yelled at me (together for 2 years), and it was because I got off work and he sat out in the parking lot for an extra half hour when he didn't need to.  

My circumstances: I had to go outside to call him, because inside there is no service; I had assumed he was going to come in the store as usual; I was picking up more conditioner and cat food and looking for some Shower Soothers for him.  I couldn't find them.

His circumstances: He has been sick for a week, he was asleep when I called him to get me, he left me 9 voicemails and my shitty phone told me (when I left the store) that he called twice, he doesn't like it when I spend money. Also, I normally walk to and from work, and sometimes I will get grocery or sale items after work while waiting for him.  He usually will come in and meet me. This time I forgot he was probably not going to leave the car so I took my sweet time.

I had forgotten how exhausted he was.. he sounded okay over the phone when he came to get me, and was sweet, then the moment I got outside to the car he cussed me out and screamed.  Because he's sick, or do I need to be more considerate, or... ?  I figured I should give him some space, so he's in bed now and I'm sitting here feeling like a horrible person because that's what guilt does to me.

When I got in the car he said "I know that you're used to these selfish survival techniques because of your family, but we are in a relationship and it's about BOTH of us now, not just you!"

This isn't me lashing out about him; I know I have been in a mental fog and really should have remembered that I've been doing nothing but babying him for a week.  He couldn't come in the store because he was in a robe and slippers, he thinks he's fighting pneumonia.
<bot>: feeling guilty for unfortunate coincidence, how do I ease the tension/will someone talk with me because I don't want to make him more angry?  God, I'm a horrible person.