Tim Drake / Robin

Post-Crisis / New Earth
During this time, Tim was also the object of the affections of Greta Hayes / Secret.
 * 1)  Lynx  - This villainess was supposed to be the Catwoman to his Batman, but it didn’t last long.
 * 2)  Ariana Dzerchenko  was Tim’s girlfriend around the tiem that he first became Robin.
 * 3)  Stephanie Brown / Spoiler  and him experience romantic tension. After he and Ariana broke up, they became an item. They were together for a long time. She is the only woman he has acknowledged as loving, and is his most significant love interest.

There was also a character named Darla Aquista, who I’m told was just a plot device to break Tim and Steph up.

4.  Zoanne Wilkins  was apparently his next girlfriend

There was apparently an attraction (possibly only on her part) with Cassandra Cain / Batgirl, but it never came to anything.

5.  Tam Fox  was apparently a girl he dated a little.

6.  Cassie Sandsmark / Wonder Girl  was the girlfriend of Tim’s best friend, Conner Kent / Superboy, all being members of the Titans. After Conner’s death, Tim and Cassie took solace in each other, and became a couple for a time.

7.  Lynx III  - This villainess apparently also had a thing with Tim.

New 52
 
 * 1)  Cassie Sandsmark / Wonder Girl  - Tim and her take a liking to each other in this reality, while Conner also likes Cassie. Trigon, while mind-controlling Tim, initiates sex with Cassie. I’m not sure how this all turned out.
 * 2)  Stephanie Brown / Spoiler  - Apparently this relationship is also teased in this reality.

Elseworlds / Alternate Universes
 DC vs. Marvel 
 * 1)  Jubilation Lee / Jubilee  - Pretty sure this story isn't in official continuity, but Tim and Jubilee team up when teir universes crossover. Before going back to their own worlds, they share a kiss.

Titans of Tomorrow

 * 1)  Bette Kane / Flamebird  and Robin are a couple in this alternate future.
 * 2)  Cassie Sandsmark / Wonder Girl  - In the same (??) storyline, he’s shown in the same (??) future to be in a relationship with Cassie. But he is evil in this incarnation and is cheating on her.
 * 3)  M’Gahn M’orzz / Miss Martian  would be the one he’s cheating with

Random Alternate Future

 * 1)  Cassandra Cain / Batwoman  and him are shown in a relatinoship while he is Batman

Future’s End

 * 1)  Madison Payne / Firestrom  - Quoting another internet user, “In Future’s End, five years in the future Tim Drake has changed his name to Cal Corcoran, has distanced himself from any superhero activities, and is engaged to a woman named Madison Payne who only knows him as Cal and not Tim Drake. I don’t keep up with this event so all I know is that Madison becomes the new Firestorm at one point, and Tim travels into the future to become the next Batman Beyond? And somehow he meets Madison in that timeline again and they got together?

==  Adaptations  ==

Arkham
 Batman Beyond 
 * 1)  Barbara Gordon / Batgirl  and Tim have a thing in this video game series, and are married in the future.
 * 1)  Unnamed Wife  - In the world-expanding comics, Tim is shown to have a wife, a blonde woman that is largely suspected to be an adaptation of Stephanie Brown.