A good thing:
You are aware of his mistreatment of you. Many abused people never recognize that they are being mistreated. It is to your credit that you now can see this. This is the first step to getting out of an abusive relationship.
You have given him many chances to improve his relationship with you, but you can also see that he either will not, or cannot, change the way that he is with you.
It is very important to know that depression cannot cause what he is doing to you. Yes, depression can make him withdrawn, sad and irritable. But, it will not make a person abandon another, like he did to you. That is not depression, that is a part of his own fear and unresolved emotional issues.
I am sure he has problems. Chronic pain, hard work, depression...all of these are significant. Yet, none of them can cause someone to be harsh and uncaring and especially: they do not cause a person to abandon another as he did to you, multiple times (!)
It is very important that you clearly see the difference between feeling sorry for him and feeling that you need him. I think you are a tender hearted person, a creative type that wants to see as many people happy as you can. That is a common personality trait for someone in fashion merchandising. But, this man is not someone that you can excuse in his actions. If it had been one or two times that he hurt you, perhaps. Yet, he hurt you many, many times and when you needed him, where was he? Somewhere else. He does not care about you. He is self centered and that is not depression, that is something else.
Although you feel that you cannot leave him easily, please see that you must love yourself enough to recognize that you are special and deserve better. You were very kind to him, gave him every chance; still, he hurt you.
Sadly, there is no real way to stop this unless you set the limits. He has been in control, now you must be in control. It is time to tell him how he must be, or that he can leave. Yes, you will make him feel sad if you do this, but he is grown man with adult responsibilities. He can deal with it and change, or he will lose you. It is that simple.
Remember, it is acceptable to relate to his pain, but you must love yourself enough to set limits on what you will tolerate. He has crossed the line too many times. He has hurt you and now must pay the natural consequences of his actions. True, it will be painful to watch him go through this, but if you do have feelings for him you will want to see him mature and grow...and he must stop being abusive, even if it is you that stops him. Steven