It's completely subjective though. Some people deserve getting taken advantage of. Like with my ex, the lesson she should take from me is dont be such a abrasive and disrespectful b1tch to someone you're sharing your stuff with and expect to be appreciated. Now she's like that with every one but i didn't give a fvck.
From her perspective she thinks I just used her. It's not that simple. The only thing i did wrong was not use that as an opportunity to make my life better and then leave her. I fell into a cycle of self destructive behaviors and she would antagonize me further. She wasn't naive and she made her choices. If i could go back id stay very emotionally distant from her, snd save as much money as i could, and just disappear. All at her expense.
Now is this an immoral way to think? I would totally get her hooked on me even more than she was before, that way in the future, if i needed something i could just call her up.