good luck!! If your boyfriend loves your yorkies it won't be hard to convince!!!
My fiance never wanted a yorkie, he had the stereotype of yorkies are yappers and toy dogs are for wimps. A manly man gets a "real dog" but after we got Pochi he was hooked, he half-heartedly protested when we got Choppi and rolled his eyes when I said I wanted a girl and when I got him to go with me to meet the breeder (1.5 hr away from us) he fell in love with Daisy and of course couldn't say no.
They are always the biggest softies at heart!