Nelly...
Welcome to the Board. It sounds like you've been through your own horrific version of hell for quite some time. But by finding us and taking the time to post, you've made a very positive step towards taking your life back.
Addiction to opiates is another horrific form of hell. Once they get a hold of someone, they simply do not let go without a fight. The fact that he's an Iraq War veteran piqued my interest; is it possible that he's suffering from PTSD? If so, opiates make sure the user doesn't feel a thing. On that basis, it's possible to see the appeal of opiates...
...until they've got you in the spiral that he's currently in.
I found this charming:
Yesterday I told his mother and he broke up with me in a text message.... Ended his engagement in a text!!!! He told me he just isn't happy and I'll never trust him...
These are the actions and the behaviors of someone whose moral and ethical compass has been disabled by chemical means. If that's what he wants, then simply give him his wish. And as Anvil said above me, stay the hell away from him from this point on.
Nelly, I know that this is a kick in the teeth for you. I know you're hurt, confused, angry...and I get it. I really do. But at this moment, it's important that you do what is necessary to protect yourself. There is no evidence that he wishes to embrace recovery. There is evidence, however, that he's dangerous to be around. So step away from the madness, and allow yourself the time and the space to heal. Things will get better, although I know you don't believe that at the moment.
Keep us posted. And again, Welcome to the Board.