How do I make my boyfriend less pretentious?

I love my boyfriend but I don't think he connects with "the real world". He is privileged and kind of pretentious. He goes to Oxford and he unintentionally acts condescending to people who don't go to Oxbridge or the Ivey league in America. He wears only designer clothes, eats at the best restaurants and lives in a mansion with his parents when he is not in school. He smokes a fancy pipe and owns a walking stick. He has a snooty accent known here in England as the RP accent. If you think of the voice of a posh English person, you are hearing the RP accent. Also, he only speaks the Queen's English (no slang whatsoever).

I come from a different background than he does. I grew up in a lower middle class family in East London. I went to a state school and I go to an average uni now. I work two jobs and still I have a tough time making ends meet. All of my friends are of similar backgrounds. They were not born with a silver spoon in their mouth and they certainly don't go to oxford.

I am embarrassed whenever I bring my boyfriend around my friends. They are all of humble origins and, consequently, they act like regular people. Then my boyfriend comes strutting in looking like the Oxonian toff that he is and makes everybody feel inadequate. He usually makes a giant arse of himself and is oblivious to it.

I think it would be a good experience for him to learn how the other half live. He can't go living his life in this ritzy bubble of his. He needs to come down from the ivory tower and learn how to act like everybody else. How can I help him become less pretentious?
How do I make my boyfriend less pretentious?
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