Publisher: DC Comics (1970-2007)
Includes: The Batman Family #1-5, 7-17, 20, Detective Comics #489, Birds of Prey #8, and Nightwing Annual #2
Clipped from Wikipedia: Barbara Gordon has been romantically linked to Dick Grayson, aka Nightwing/Robin. At a young age they shared their passion as Robin and Batgirl.
Nightwing was shocked and disturbed to learn of the effects of the Killing Joke, resulting in Barbara's paralysis. After the events of No Man's Land, the two fall in love.
Before Infinite Crisis, Nightwing drops to one knee and proposes. Barbara tearfully accepts. When Batman asks Nightwing to help him rediscover himself, Dick is hesitant due to his engagement to Barbara. She allows him to go, telling him they were not ready for marriage.
Before Dick leaves, he sends her an envelope with her engagement ring and picture of them together as Robin and Batgirl.