DO IT for her

This is because in Varmints, Marceline hasn’t spoken to PB for at least 2 months. She has no idea about anything that happened in the season 6 finale. And PB is still pushing people away. But at the end of this episode, when PB fully opens up to Marcie for the first time, and Marcie provides much needed support and understanding, I think this is when things got a bit more serious between them. 

Marceline and Bonnie in Stakes are crushing hard on each other, and they’re starting to think about the future. However, I think their feelings about each other are complicated enough, as are their feelings about Marcie’s de-vamping, that they can’t have a sincere discussion about how Marceline’s mortality will affect their future. Bonnie provides her full support, and says Marcie will live a fully happy mortal life, and she’ll be the one to bury her in the ground when she dies. The romantic implications of this are obvious. However, the underlying subtext is that PB is pushing down her true feelings of the matter, and Marceline hasn’t thought about the impact on their relationship.  

In the episode with the Moon, Marceline starts dying due to poison. She starts dreaming of her desired future life as a mortal. Bonnie has to deal with the concept of Marceline’s death then and there - taken away so suddenly, without any time to process it. Bonnie is struggling to keep herself together, and asks Peppermint Butler for help using suspicious methods that she doesn’t understand.  Marceline imagines her own death, with PB at her side still young and pretty, and it’s not a bad reality at all - Marceline lived a happy life in her dream world - but she’s also started wondering what it means to get old and die while her partner has to watch. It’s a difficult situation.  Bonnie’s crying ends up being the thing that wakes Marceline up, alerting her to the presence of the Moon. 

Anyway it’s in this episode that they were hit with a steel chair reminding them of what they mean to each other. 

They still had some more obstacles. Marceline had some growing up to do in Stakes, and she kind of ditched PB at the start of the final battle. But Marceline spoke to Ice King and realised that she’d been strong the whole time, and she took destiny into her own hands. It was the power of her bonds with others and of her newfound respect for herself that she used to kill the Vampire King. Bonnie got to watch this happen.    

Even though Marceline had been re-bitten, she was at peace with this now. She’d reclaimed her vampirism with dignity, and owned her trauma. She is happy to remain a vampire because this time, she has her friends to help her.  “Now I guess we can be together forever.”

PB is clearly interested at this point in pushing their relatioinship forward, because she invites her to live in the castle. Marceline rejects at the moment, but in this episode, they had become committed.  

It’s after this that you see far more moments with them holding hands, Marcie taking PB to a dinner date with Simon, both of them hanging out in the skate park, Marcie singing more love songs ripped from lgbt artists, both of them REPEATEDLY trading clothes (sometimes within the same scene like in Islands Part 1), the whole situation where Marcie was by PB’s side singing songs about love for the entirety of Elements and it was revealed later that she CHOSE to get elementified because she thought there was no way to bring PB back... and then the final season, where Marceline is seen as PB’s strongest ally by her worst enemies.  The final episode, where Marceline confronts PB about the war and asks her not to do this, but even though they’re together and having a sincere conversation, they’re still not on the same page because PB is putting this battle above everything else, even though she shows her first signs of conflicted feelings when Marcie talks to her.  

When Marceline sees PB “die”, she is overcome with rage, and the power of her heartbreak causes her to turn into Dark Cloud and DEMOLISH the enemy horrorterror. When PB survived, Marceline launched herself at her into a hug, and PB seemed unsure of how to respond to Marceline just pouring her feelings out about how even when they weren’t talking, she was still so worried something would happen to her (makes me wonder if Marcie ever found out about Mortal Folly/Recoil). PB tries to reassure her that nothing will happen, which turns into a funny joke because of her concussion, and they laugh and kiss like it’s the most natural thing in the world. After all, they’ve been a couple for 3 seasons.