<human>: When does it cross the line and become verbal abuse? 

I love this man and have spent two lovely years with him but I have a history of being in unhealthy relationships and he has a history of being explosive. Not really violent, but he gets very angry over something more or less trivial and then cools off quickly like it never happened. He does tend to punch walls, break things. He got into a bar fight last week for the first time and hit an innocent bystander. 

We were having a silly debate over the phone and he just lost his temper out of nowhere, he said I was stupid, dumb, uneducated (I'm in grad school). I tried to correct him and say you mean what I'm saying is stupid, and he said no, you're stupid. I always thought you were smart, but you're actually just stupid. 

I'm not sure if I'm being overly sensitive. Is this just arguing on the phone? I could really use some advice. 

Please understand that I have never loved someone so much. He makes me happy in a way I didn't even know was possible. We've traveled the world together and laugh together and learn together. I want to spend my life with him. 
I'm so confused...please reddit?

Can you summarize the given text in a few sentences?
<bot>: my SO hurled insults at me out of the blue and I'm afraid it's a red flag and don't want to end up with blacks and blues.