In your shoes, i would do this (though i dont know the background so unsure as to whether it would work).
For Ashley: Disown him, let him know how 'not cool' <-- good word for it

his actions were. Let him know you know about him and what he did to Daniel last time he was drunk, and tell him that he needs to change his ways or he's going to lose everyone he knows/cares about. If he refuses, grouply disown him.
For Daniel: Tell him to try his best to stay out of things, but obviously in a perfect world, he should/would get back together with Amarise.
For Amarise: Ideally get her to have a chat with Ashley. Make sure she makes it clear that in their relationship, there can be no occurances such as these. Make sure she takes control, and makes sure that Ashley knows she could walk away at any time.
All i can think of for now

Good luck with this, lordy o.O
~Mugger84