I have 2 male dogs. Mojo, my yorkie, is also a little over 1 year, Byron, our rescued chihuahua mix e about 2-3 yrs old. They get along fine, but there is one thing i was alerted at the begining, they will be disputing the territory and "marking" everything as their own, meaning that they would be "lifting" their little legs everywhere. I have not seen that happen and they've been together for over 6 months now and they are the best of friends. Now Byron is leaving me
and i will definetly buy a female yorkie, so i am also hoping that they will get along good.
It would be good to pay attention on how he interacts with male and female...that will help you make ur choice.