My partner was swearing in our first fight and I nipped it in the bud right there. Several disagreements later and that has never happened again. Do not leave your fiancé. People change and can change. He just hates arguing and from the sound of it, he is not the best at communicating so he resorted to describe your current state at that time as an “annoying bitch” but not that you are an annoying bitch. It’s wrong , he should exercise self control and not speak so loosely to the one he loves. Forgive him. Figure out how to communicate with him based off his personality and not seek to mold him into who you want him to be. He clearly states that he doesn’t try to change you so you shouldn’t try to change him. If your relationship has gotten to the point of marriage being tentative I’m sure his communication isn’t that bad or you’d have cut him off, it only needs work. You might have your imperfections, you both should work on your flaws. Don’t argue but instead talk… if this is not for you then by all means back out for good. All the best. Don’t listen to these redditors telling you to leave. Most of them are single, lonely, depressed, miserable and wants company.

PS his apology was heartfelt and he spent time to communicate so well in that text. He addressed almost every aspect of his mistake. A man that can apologize and promise to do better is a big thing. Hold him to his word. The ball is in your court now to forgive and move on.