Boys buy mobile phone cases and laugh at me.

In your understanding, it may be friendship between friends. You have no idea, and there is nothing wrong with it. But if you look at the problem from the boyfriend's point of view, what does it mean for a boy to give you a gift? If he is a close friend, or a friend familiar to his boyfriend, he won't have such a big reaction.

What do these reactions show? Explain that your boyfriend likes you, loves you, cherishes you and is afraid of losing you. Therefore, he is hostile, angry and even more angry with the boy who gave you something. You didn't refuse the gift because he thought you didn't care about him, which made him feel a sense of crisis.

This may be good in some cases, but there is also a bad side.

Therefore, when you are mature, you still need to practice. Actually, there is nothing to be angry about. If you like your boyfriend, you should be happy. Besides, your boyfriend is also at fault. He is stingy and has no self-confidence, and can tie you firmly to him.

Maybe that's why he's angry and you're angry.