8 Theories About The Origins Of Heath Ledger’s Joker
3. Its All About His Wife
The second of the scar-origin stories sees them repurposed as a sign of love; his gambling addict wife was attacked by loan sharks, so in an attempt to make her feel better he did the same to himself, to her utter horror. It's a sad tale that, once again, has a whiff of the fantastical to it, but could serve as an interesting alternate explanation.
Notice how after killing a Commissioner and a Judge, as well as trying to off a District Attorney and the Mayor, that Joker goes for Rachel. It's a bit of a step down in terms of public status, which could have been brought on by some sort of obsession with her. She's the only woman he really directly interacts with and he immediately makes her part of his plans; he puts a lot of effort into using her as a weapon against both Batman and Harvey Dent. At the very least there's distinct sense of some sexual repression in there.
What makes this interesting is that unlike the father excuse there's a strong suggestion Joker was already in his descent; cutting yourself in an attempt to make someone feel better suggests a distinct lack of empathy.