So being extremely generous to him, with him being a student he's clearly still immature. But honestly that's all I have to mitigate this, because I remember what it was like being a student, and my views on relationships and sex have matured a lot since then. However, even at that age I did not at any time think it was my girlfriend's role to "please me". I'm not saying I wouldn't have gotten into a mood on occasion after being rejected when I wanted sex, but I would never have referred to have girlfriend in those terms either, and wouldn't even have gotten into a mood if my girlfriend was on her period and in obvious pain. I am wary of not simply assuming that something is unusual because I didn't think the same way, but I really don't think it's normal to act in that way at any time, but particularly not when you're suffering with bad period pains, and it's also not normal to accuse you of demasculating (I assume he meant emasculating) him. Being disappointed and not getting sex is one thing, but suggesting that it is your fault when you have such an obviously good reason not to have sex is not good, and hints to me at attempts to control and gaslight you. Not an absolutely clear red flag. I'm not jumping to the most serious conclusion and telling you to break up with him. But that behaviour is completely unacceptable and not something you should tolerate. If that is not an isolated incident or not out of character, you absolutely should be breaking up with him.