Funny, I've run into a similar situation before. There was an Armenian guy who gave everyone an Americanized version of his name but I knew it was wrong right away (I'm not Armenian, I grew up near Glendale). I called him by the correct pronunciation and it actually upset people a touch for a few days when they found out that he was letting them pronounce his name incorrectly (people asked why I was pronouncing his name wrong). People felt like he was walking them into a trap, I guess? Or thinking less of them for their inability to immediately pronounce his name correctly? And they felt bad, like they were mistreating him, and he was trying to be polite but it didn't help. In the end everyone learned to pronounce his name correctly.

Perhaps your boyfriend would like an opportunity to pronounce your real name correctly? So that not only a few limited people say it? You can say to him, "He isn't special at all to me, he just knows how to say my name correctly. Anyone who can say it correctly can call me that, is that okay?" And if he wants to learn, offer to teach him. Otherwise, perhaps he can give you a special nickname. At a certain point though, he should recognize this really has very little to do with him or this particular guy.