Well, I guess you should remind him that you do come from another culture and that he should not place high expectation on you to also change too. Not too quickly any way. I can relate to this because I was also expected to do this for work in an international environment, it is tiring. You have to slowly adapt a little bit, but in your own time.
Well, I was annoyed he spoke to me like that but didn't want to create an issue so I let it go saying that I was really tired (true) but how could I have handled it better? I feel as I have let myself down and I should have stood up for myself and should have told him I don't appreciate e speaking to me like that.
So when he did a negative thing, instead of "fighting" directly, you can indeed be vulnerable and let him know that it hurts you or show that what he said did offend you. You may feel let down because you did not choose the right response. If you chose the right response in that moment, you will feel better. Being defensive, or avoiding, can lead to resentment, and anger.
When someone accuse you and that they are not aware of it. If you just say it slowly, and reflect what you feel, then they can recheck and will maybe respond differently. Instead of reacting to his verbal accusation with a verbal response of your feeling, why not "state" your feelings or what you think it sounded like. i.e. "that sounds accusative, it sounds hurtful". I normally use these "uncertainty" words like "sounds like" when it is someone else's expectation of me, and not how I see the situation. He needs to address his own words, and either apologise or directly respond to it more appropriately and accurately.
He would than say that he did nothing wrong and I was over reacting and we would start arguing...
Because you reacted with negative emotion, i.e anger towards his negative emotion, he would "deflect" rather than insult to diffuse the situation, and that is why he then again say it is your fault. Cos he is again judging you by his goggles. But neither of you should judge each other by the other person's goggle, but really to be open and build gaps and bridges. You can only understand him if you become honest and truthful with how you feel too.
That is why I asked you very early on, do you still want to be in this relationship because the motivation to change behaviour has to come from your own heart. The desire has to come from you, otherwise things may not shift or move a certain way.
If you watched that clip of Julia and David. He genuinely have affection for her, so even when she accused him of forgetting her birthday, he actually responded directly and appropriately, also shyly too of what he had done. They must have mutual trust in order to be able to do that. You got to ask yourself if both you and your partner can trust one another implicitly, and to also be able to show one another when you both are vulnerable. Cos only then do you be able to take care of one another's word. But their relationship also exist in this state now because they do also continually try and build up to this point. Even though you can see that they have different personalities.
You may say to us that he "should" know, but he may not be "able to" behave in a certain way unless both of you try to accommodate one another and find mutual grounds. Also, sometimes even as fully grown adults, we may "drop the ball" but allowing the other person to actually room to adapt and pick things back up again is what makes us human.