Finn. Sure, Mordecai's attraction towards Margaret perpetuates most of the show (even when he's in a relationship with CJ) but the thing about it is that when you get down to how subservient he actually is to either of them it's really nothing to write home about. He does autistic shit relating to women a lot (see him literally killing Rigby, see the wedding speech, see the breath mint episode, see the towel, etc.), but he's not doing that shit specifically FOR Margaret, or a woman in general; he's just got unrelated character flaws.
Finn is both literally Bubblegum's mule boy for most of the show and (given how this matchup seems more centered around how they act with women than their degree of subservience, a category that Finn wins easily anyway) a raving fucking psychopath towards Flame Princess after finding himself interested in her. He spends an entire episode stalking her, culminating in a chase sequence that's framed like a horror movie as she flees in terror from the sweaty freak behind her going "haha i'm probably coming off as creepy!!"
He then, in a later episode, decides that it'd be a good idea to blackmail her and Ice King to make each other fight to the death, because he had a dream telling him to do so. Finn is such a pathetic, emotionally stunted creature that she would rather be romantically involved with a literal mouth-breather over him.