Bubbline was truly the unexpected yet anticipated ship to become canon in 2018. Not to mention how much sense it made after eight years of waiting.
They were lovers before the show even aired, but they had to break up because PB had her new role as princess at the Candy Kingdom which forced her to be isolated and Marceline felt like she did something wrong that made her do that, which made her gain self doubt. Later on in the show, their relationship blossomed into the something beautiful with more communication and trust.
In What Was Missing, they have a few arguements hinting the emotions they feel about their post break up. Marcy is teasingly annoying PB for leaving her and PB is agitated by her childish antics.
(Marcy: Looks like you’re not as perfect as you though! Guess you can’t judge me anymore.
PB: *angrily* I never said you had to be perfect!)
(M: Just keep it cool. Got that, princess?
(M: They got out, because YOU let them get away.
(M: *singing about her feelings*
PB: Marcy, that’s too distasteful!)
Marcy sings, “I’m Just Your Problem” which is her basically saying, “I’m supposed to hate you for leaving me but I can’t because I still love you.” The song was so emotional and full of confessions that it almost opened the door, but she got distracted and stopped.
PB is shocked when she sings, because she didnt know that Marceline still had feelings for her after all these years.
(PB: *staring in shock*
Marcy: *blushing* Stop staring at me! Ugh, you threw me off!)
Marcy even spits on PB’s jacket and hisses at her. PB is shocked and walks away in horror. Marcy cries a bit too.
At the end of the episode, the two girls team up to help Finn unlock the door. When getting back their items, we see that PB still has Marcy’s t-shirt from when they were dating, a sign that meant PB still cares about her and misses her as well.
In “Sky Witch”, Marcy and PB try to get back Hambo fron Maja The Sky Witch.
((Also PB sniffing Marcy’s shirt in the beginning of the episode and keeping a photo of them in her closet))
To me, they’re more “frenemies” than “enemies” in this part because if they were true enemies, PB wouldn’t have helped her in the first place. She’s willing to help because she sees her as a friend, but has trouble with agreements because they’re polar opposites (Strict Nerd and Outgoing Punk).
In the end, PB trades Marcy’s shirt for Hambo, her one memory of their love life.
In “Varmints”, PB loses her kingdom and hides away in a small shack to clear her head. This is out of character for her, so Marcy grows concern and checks up on her. She also gets mad at why the King stole her kingdom as well.
PB feels useless, so Marcy tries to cheer her up with a ketchup story. The story was very ‘distasteful’ (How the old PB would put it) but she laughed at it instead.
When they got into the mine caves, PB says that the kingdom kept growing and every day something happens, and Marcy asks, “Is that why you stopped talking to me?” PB was about to explain why until the Varmints came.
When they hid in a cave, they found a tally mark PB left when they used to date. PB then cries because she feels helpless that she lost everything, she feels terrible for pushing Marceline away, and she feels selfish for being a jerk to people because of her job.
(PB: I tried. I really, really tried. I just..I thought if I could just shut everything out and focus on work it’ll all be okay. And look where that landed me.)
((Even though she is a control freak, it’s not really her fault. Her family is a herd of control freaks and tries to not be like them in any way, but fails. She did push Marcy away on purpose, but was too scared to confess why because she’s not used to openly expressing her feelings to people.))
She then apologizes to Marcy for “being a real dinger to her” and Marcy says “Come on. What are you even apologizing for?”
((This is a MAJOR growth for Marcy. If she was still in her ‘season 2 phase’ she would’ve laughed carelessly and refuse her apology or rant about how she’s only apologizing to cover up her ‘ego’. Instead, she comforts PB and realizes that being royalty isn’t easy, so she understands why they had to break up.))
At the end, they both sat on the porch. PB confesses that she’s been tired for a long time. Marceline volunteers to watch her pumpkin patch. PB then lays on her shoulder tenderly and asks to wake her up in 15 minutes. Marcy promises. They both immediately reconcile their relationship together.
In the “Stakes” series, their relationship is romantically hinted in some situations. I’m too lazy to explain ever episode, but I will say that I have a possible theory: After the events of Varmints, Marcy asks PB if they want to give their relationship another shot. She accepts, but says that nobody can know yet.
Marcy agrees and they’re secretly dating, which is why neither of them are interested in Finn, they’re holding hands again, they’re always seen together, PB is starting to accept her emotions more and adjusting to be less strict, Marcy is mature and is comfortable in her own vampire skin, and they both show genuine concern about each other.
In “Broke His Crown”, the couple get invited to a dinner with Ice King. PB still doesn’t trust him, due to their past, but Marcy begs her to try to have fun tonight. Bonnie then trusts Marcy and says she’ll try (for her).
The rest of the episode consists of the couple trying to rewire Simon’s crown from going beserk.
Some additional quotes:
(Marcy: Yeah, you always know which button to press. I’m referring to the fact that you know how to annoy me.
PB: *smirking* Yeah, I got that.)
(Simon: So, you got a boyfriend yet?
Marcy, remembering Ash: Hah! No..uh, no.
(PB: What? I don’t like relaxing. I like science.
And finally, In the season finale, Come Along With Me, PB was crushed by a giant monster (not really). Marcy panics and turns into her demon hybrid form, destroying the monster for attacking her girlfriend. When she turns back to normal, Marcy hugs PB with relief, saying she scared her.
(Marcy: Even back when we weren’t talking, I was so afraid something bad would’ve happened to you and I wouldn’t be there to protect you and…I don’t want to lose you again.)
((This is evidence that even back in the series, when Marceline was mad at Bonnie, she still cared about her and wanted to protect her from harm.))
PB responds that with Marcy by her side, “nothing will never happen to her”, meaning that PB feels more safe and comforted with Marcy by her side again. The two share a tender kiss afterwards, explicitly confirming their relationship.
(Side note: that kiss didn’t look like a first time thing. They definitely kissed each other more than once before.)
So yeah, it may not be as accurate or as detailed, but these are my two cents on the relationship on Bubbline 💖🖤