Brian's girlfriend is Leighanne Wallace, an actress who has been in such films as, "Wild America", and "My Fellow Americans". (You can check her out in her new movie, "Olive Juice", at: http://www.olive-juice.com)
Leighanne was also in the Backstreet Boys' "As Long As You Love Me" video and she played Brian's girlfriend in the "I'll Never Break Your Heart" (the second, American version) video.
According to most sources, they've been together since February, 1998. She also has been said to be very nice to fans and she had a front row seat at the New Year's Eve show (Homecoming: Live In Orlando) on December 31, and she chatted with some of the girls who were sitting nearby.
Leighanne actually found her and Brian's dog Lil' Tyk' (correct spelling) when she was walking by a pet store and right when she saw him she knew it had to be their dog so she called Brian on her phone and they bought Tyk' together!