<human>: My BF is a great guy and we get a lot very well. We tell each other EVERYTHING, or so I thought. Then I see on his Passport today his name is not what I thought it was. I was totally blindsided. He said he's always gone by his middle name and he doesn't even think of it as a big deal. I can't believe this would never come up after three years. It's a really unique name and I've never heard it come up in conversation or even from his family. I'm really stunned and he's mad at me for "blowing it out of proportion" (I'm not angry, just really, really confused) and that I need to "never bring it up again".

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: Just found out BF of 3 years legal first name. He's upset at me for being shocked and I don't know why.