I will not advise you on what to do since I don't know enough about both of you. But do I get hurt when the closest person to me mock my stuttering? Yes, it is like sticking a knife into an already opened wound. The memory of it alone is enough to hurt you again. Since most of the comments here are strongly on your side, with good reason of course! I will try to give you more of an objective point of view If he is young, he might got little bit defensive and his “gamer” mode has turned on and took the opportunity to lower your grounds. He might just did it because you stuttered but not because you have stuttering (I mean he would do the same if you didn't have stuttering). Since you already got hurt it wouldn't hurt that much to confront him about the incident specifically of why he mocked your stuttering despite him knowing you have sttuering, say that this mocking gave you bad memories about bullying and see his response, he might apologise for mocking you but that doesn't mean he is sorry for arguing with you in the first place. The matter of the fact here is that you got hurt really badly, his response would not change the past of how that incident affected you. But if he apologised after knowing how you felt, you might give him a second chance. If he is not young (24+) then idk, its a red flag that someone this old still can't argue respectfully, if he mocked of how you sound I wouldn't be surprised of him mocking you of how you look just because you had an argument.