How Can I Make Him More Accountable in Relationships?

You do have resources inside of you that if a stranger or an acquaintance did this to you, you would have more resources from which to draw. Introducing certain components of those resources into a romantic relationship can start to bring certain levels of awareness and show the other person that you're not going to be as tolerant of bad behaviour any more. If he sees that you're suffering and he's still not changing, then something else needs to change. At least if you care about your mental health and well being, there might be a new direction you have to take. And above all, and this is something i absolutely know to be true, you are amazing. I wish you much strength and healing