Looking around online, it's easy to get the wrong impression about the Joker and Harley Quinn. With all the fan art, t-shirts and "his and hers" merchandise of the two of them (there are even matching engagement rings for God's sake), you'd be forgiven for thinking that they're one of the most romantic couples in the DC Universe.
No. A thousand times no. The whole point of their relationship that people seem to be missing (thanks a lot Suicide Squad) is that it is a toxic and abusive one. Joker is a cruel and sadistic monster who only keeps Harley around as a punching bag for when his plans against Batman fall apart.
It's a situation that Harley puts up with because her "Puddin" has broken her psychologically to the point that she's completely dependant on him. Even when she's fully aware of what a monster he is, it only takes a single act of kindness for Harley to go running right back to him.
It's a really horrible relationship that has been defined by all the terrible things that Joker has done to Harley over the years. From emotional neglect and psycological abuse to flat-out physical violence, Mistah J's lowlights have occasionally made for some pretty uncomfortable viewing...