Dick Grayson

Earth-Two

 * 1)  Vera Lovely 
 * 2)  Marjory Davenport 
 * 3) Helena Wayne / Huntress - It is clear that, after he watched her grow up and she became the superheroine Huntress, Helena and Dick were in love. She was, however, dating District Attorney Harry Sims. When Sims proposed, Helena was conflicted because of her feelings for Dick Before she could give him an answer, Harry suffered an attack by the Joker which left him comatose. This is the last of the story this author knows, and it is also unknown to him if this has any basis in the Earth-Two reality.

Earth-One / Post-Crisis / New Earth
When he was a teenager, Dick and a girl named Liu became very close, and he even lost his virginity to her. Unfortunately, Liu was revealed to have ulterior motives and was basically using Dick for his connections to Bruce Wayne. (Nightwing #133-137)

1.  Roberta the Girl Wonder  (Star Spangled Comics #103)

2.  Edie  (Batman #156)

3.  Bette Kane / Bat-Girl  - When these two would have adventure together, sexual/romantic tension inevitably played a part, including at least one kiss.

4.  Lori Elton  was Dick’s girlfriend in his early college years, around the same time he was gaining a crush on Barbara.

5.  Barbara Gordon / Batgirl  - These two also fought crime side-by-side as teenagers, and had a certain romantic chemistry and tension. While relaxing after a tiring fight, Dick took the time to divulge his feelings for Barbara, only to see that she had seemingly fallen asleep. In fact, she was awake, but was unwilling to respond to his confession. (Nightwing Annual #2)

6.  Koriand’r / Starfire  When Koriand'r first encountered theTitans, In an attempt to learn English, she absorbed the language by planting a kiss on Dick. This left him flustered, but meant nothing romantic at the time. (New Teen Titans #2, 1980)

During this time, Dick apparently kissed Raven once (likely for innocent reasons) and, due to her own inexperience in the world, she came to believe they were in love. It was later explained to her that Dick did not love her, and, in truth, she likely did not really love him.

Initially denying his feelings for Kori, Robin realized how much he loved Starfire when her life was threatened by her sister Blackfire during an outer-space adventure ( New Teen Titans #23-25, New Teen Titans Annual #1, 1982). In the heat of the battle, Robin’s burgeoning feelings for Starfire became obvious. The two fell in love and became a couple.

It was later revealed that Barbara had come to Dick’s apartment once in an effort to kindle something between them, only to be greeted by Kori in her underwear, then walking away crying. (Nightwing Annual #2)

Dick and Kory faced their greatest challenge when Starfire was forced into an arranged marriage to quell a Tamaranean civil uprising. While Starfire saw this as a marriage of state, Dick felt betrayed and left his alien love on Tamaran (New Teen Titans, vol 2, #15-18, 1986). Starfire eventually returned to earth, and reconciled with Dick once he learned she did not take the traditional Tamaranean wedding vows (#39, 1988).

The shape-shifter Mirage later kidnapped and impersonated Starfire, causing strain in her relationship with Nightwing. Impulsively, Dick proposed marriage to the tempestuous Tamaranean, desperately hoping to mend their relationship, and she accepted

Dick was off-planet when Barbara was paralyzed. When arrived and heard the news, he came to her apartment, and the two fell into an embrace, sleeping together. Afterwards, he gave her an invitation to his and Kori’s wedding, causing an infuriated Barbara to kick him out. This type of behavior was later attributed to an evil possession on Dick’s part.

Dick and Kory's wedding ceremony was interrupted by Raven, now reborn as an evil avatar of her father, Trigon (#99-100, 1993). Starfire was implanted with a demon “seed” by Raven, which caused her to leave Earth and go on a spiritual journey (NTT#114 & Showcase ’94 #11, 1994). Thus, the long-standing relationship came to an end, with neither party acquiring much closure.

Kory later returned to Earth. Although they have succumbed to old passions more than once, the pair have decided to remain good friends above all else.

7.  Bridget Clancy  was the superintendent of Dick’s apartment complex when he first moved to Bludhaven. The two quickly became friends. Both seemed to want more, but then Dick began to grow closer with Barbara again, and Bridget moved away.

Nightwing paired up with anti-hero Tarantula with the hopes of getting her to act more heroic. With the two spending so much time together, Tarantula eventually developed feelings for him, though Nightwing never really reciprocated them. Unfortunately, Tarantula definitely took things too far when she had sex with Nightwing in a weakened state, raping the hero. (Nightwing #93, Jul. 2004)

8.  Cheyenne Freemont  - The child of two metahuman parents, young Cheyenne witnessed firsthand how people reacted to others with powers, as her family was run out of town due to their strange abilities. When her own powers emerged, she kept them hidden for fear that people would hate her as they did her parents. Her flair for design led her to become a famous clothing designer. She was content to live a normal life, until she crossed paths with Dick Grayson, the superhero known as Nightwing.

After Cheyenne spent a night with Dick, a man who had feelings for her proceeded to beat her for her tryst with Dick. Cheyenne used her psionic powers to blast him away with a force bolt. Later, when Jason Todd threatened her, Dick (as Nightwing) came to her rescue, only to become an accidental model in her fashion show. Cheyenne learned that Dick was Nightwing, and Dick learned that Cheyenne was a metahuman. He tried to convince her to become a superhero, but she refused, not wanting to expose herself as a metahuman. Only when Jason Todd became a prisoner of two super-powered brothers who intended to kill him, did Cheyenne use her abilities to help. She created a costume similar to Nightwing's and used her powers to help Nightwing save Jason, before retiring as the female Nightwing. (Nightwing #118-124, 2006)

Dick and Babs eventually began dating again, and became engaged. But they too eventually broke up.

9. Deborah Poulos ("Freefall," Nightwing #140-146, 2008) was an employee at the Cloisters Museum, where she met Dick. They started dating, and when she decided to move to California, she asked Dick to come with her. He turned her down, and the relationship ended.

Dick has also been the unrequiting recipient of the teenage Supergirl’s affections after her return in the 2000s, with her planting a kiss on him.

New 52

 * 1)  Koriand’r/ Starfire  - Dick apparently has a similar history with Kory in the New 52. After returning from Tamaran, she says she can no longer remember Dick’s name, or many details about him, as Tamaranians lose their memories when they leave a planet (or some crap like that). It later turns out she was probably largely fibbing about this.
 * 2)  Shawn Tsang / Defacer  - This leader of a group of rowdy outlaws also held a position at the community center where Dick Grayson volunteered, and as such, they knew each other in both lives. After giving up her criminal ways, and having Nightwing help her and her old gang out of a jam, she confessed that she knew Dick’s true identity, and for a time, the two date. (2016-???)
 * 3)  Barbara Gordon / Batgirl  - These two often flirted while fighting crime together. Eventually, Dick made it known he wanted more from their relationship, but she chose instead to date Luke Fox / Batwing.
 * 4)  Sonia Branch  and Dick's relationship ended when he discovered she was the daughter of Tony Zucco, the man who had killed his parents.
 * 5)  Agent 8 -   Once his identity was revealed to the public, Dick went undercover as an Agent of Spyral. Once there, Dick did several missions for the agency before returning to the mantle of Nightwing over a year later.
 * 6) Raya  

Dick has apparently also been the unrequiting recipient of affections from women named Jessica Cruz and Sophia.

Kingdom Come

 * 1)  Koriand'r / Starfire  - In this continuity, they are married with a daughter.

Nightwing: Origins

 * 1)  Bette Kane  and Dick are married here.

Other Alternate Futures
The specifics of these are unknown to me, except that in some he ends up with Kori, and in others, Barbara, and in one, Bette

Convergence

Future’s End

Batman Annual: 40 Years Later

Endgame

DC Animated Universe
In Batman & Harley Quinn, which is reputed to be apart of the DCAU, Dick has a sexual encounter with Harley Quinn while she has him tied up as her prisoner.
 * 1)  Barbara Gordon / Batgirl  and Dick dated before they realized each other’s alter egos, and at least had an attraction to each other after..

Batman & Robin

 * 1)  Barbara Wilson / Batgirl  - Dick has an immediate attraction to Alfred's niece, who later becomes his teammate and, apparently, housemate.

Teen Titans

 * 1)  Koriand'r / Starfire  - Apparently these two have a romantic tension here.

Young Justice

 * 1) Zatanna and Dick share an attraction, and at least one kiss.
 * 2)  Barbara Gordon / Batgirl  - In the comics spun off from the series, these two share an attraction.

DC Animated Movie Universe

 * 1)  Koriand'r / Starfire  - They also share at least a tension here.

Titans

 * 1)  Dawn Granger / Dove  and Dick fought crime together when he was Robin, along with her partner, Hank Hall, AKA Dove. She and Dick dated, and according to Donna Troy, Dick "fucked that up." After their breakup, Don began a relationship with Hank.
 * 2)  Koriand'r / Starfire  and Dick were attracted to each other during their mission together to save the young girl Rachel Roth. This included sleeping together multiple times. At the time, Kory was suffering from amnesia and Dick was trying to figure out who he should be They told each other when they had sorted these things out, they might "Try again."

When Dick was shown a hallucination of an ideal future by the demon Trigon, he saw himself married to and having a family with Dawn.