No, she had a crush on Ace in the episode "Buttercrush", which was hilariously alluded to in "Aspirations".Soxafloppin said:While we'er talking about PPG..
Was Buttercup supposed to be a Lesbian? I all ways got that vibe from her.
Bubbles: The Gang Green Gang? You wished for them?
Buttercup: No!!
Bubbles: I thought you were over them.
Buttercup: Why do you got to bring up old stuff?
Oh, Buttercup.
Actually, now that I think of it, City of Clipsville shows them all having crushes on the Rowdyruff Boys when they went into the future and became teenagers and gave up fighting crime to hang out at the mall.