So I personally think that under the current circumstances, you can choose to be with him, although I know that it is very painful for you to be with him in this situation, and you are very painful in the process. Your attitude towards him will certainly not be particularly good, and he should not feel so happy. But in any case, breaking up will not be a big blow to him, so the best way now is to endure it first. Since he is preparing for the exam, it means that he spends most of his time studying in the library, and you won't spend too much time in contact, so there is not much difference between falling in love and not falling in love. Next, I'll talk about the reasons why I don't suggest you break up at this time.
Avoid complaints from boys. Emotionally, I am really afraid of being accused by the other party. Whether I am still in love or after breaking up, I don't want to hear anything bad from my other half, especially such a matter concerns my future and destiny. I don't want to get into the reputation that he didn't get into the exam because I broke up, so I really don't suggest you break up at this time, so even if he doesn't get into the exam, he won't blame you.
Give boys a buffer period. Of course, you can also give boys a buffer period through this stage. After all, after you have the idea of breaking up, your attitude towards him will definitely be different from before, and the feelings between you will definitely fade. Plus, he is busy studying now, so he doesn't have much time to think about it. After the exam, he will adapt to the cold relationship with you now, and he will naturally accept the breakup.