AITAH for breaking off a long term relationship over the use of the c word

Title sums it up. But TLDR I just ended a 4 year relationship bc my bf called me a “ f**ing cnt” in an argument. We had a political disagreement on immigration where he felt I was directly attacking him and not the policy I disagreed with (one that happened to directly affect me and family members of mine). I was away so we talked over the phone and we maybe discussed it for 30 minutes cumulatively over 2 days. On the third day we had an hour long conversation where it escalated to him yelling and calling me that and also bringing up that one of his patients (who is apparently has worked w me) spoke ill of me recently of my capacity in the professional setting as a (we both work in healthcare) but refused to say exactly who or what was said…just that it confirmed to him I’m a terrible person. He eventually hung up and that ended the conversation. He is also refusing to tell me what was said about me saying he doesn’t wish to disclose it and it’s not relevant.

I tried really hard to explain I felt disrespected. He defended it by saying he felt I was attacking him and that calling me the c word was the only way to get me to stop as I wouldn’t back down. He also said in context they were just “two words” and it was an error on my end to end an entire relationship over these words. And that I was acting rashly. He also tried to justify that in an argument a few months earlier he had called me that (although immediately apologized) and I had forgiven him at the time. Although to be honest there was a high stress situation going on around us and I had barely noticed.

Up until this argument, we were doing well. Yes we had ups and downs like most couples. But our fights had not escalated to this level. And for the most part it had been a loving and supportive relationship. We tried talking it out for 10 days and then I asked him not to contact me for 2 weeks when he did not apologize. However speaking to him again he still maintains it was excessive to end a relationship over those 2 words.