Harley and Ivy have had an on-again off-again thing going since the late 90’s or mid 00’s. It’s been at least decade since Harley ditched Joker in the mainline comics and moved on to greener pastures.
They actually first implied it during the Batman: The Animated Series, as a “Sappho and her friend” style relationship, only coming out and saying it later in the comics.
Harley and Ivy have had an on-again off-again thing going since the late 90’s or mid 00’s. It’s been at least decade since Harley ditched Joker in the mainline comics and moved on to greener pastures.
They actually first implied it during the Batman: The Animated Series, as a “Sappho and her friend” style relationship, only coming out and saying it later in the comics.