You’re with Slade

You were once his girl, his lover, but now you’re just an ex who left him for that old psychopath. Jason knows Slade likes young girls he can manipulate and use however he wants.

TW: he can get aggressive and he uses very degrading and foul language

There is no stablished reason why you left him, so you can just ignore that bit or make up your own reasoning and backstory.