Hi, I'd like to help you with your question.
From what you said, you sound very clear about what was going on in your relationship. You were able to see your boyfriend's behavior for what it was- very controlling and hurtful. Although his abuse as a child would explain his acting out towards you, it does not excuse how he treated you.
It was wise for you to remove yourself from the relationship and protect yourself. However, I suspect that your subsequent depression was caused not only by your breakup, but the loss of a potentially good relationship and the expectations you had for you and your boyfriend. Any loss like yours is going to cause a period of mourning. This is normal and expected. However, the fact you continue to talk with him is of some concern. Not so much that you speak with him, but the potential for him to hurt you again. The fact that his last girlfriend is saying the same things about her relationship with him that you said only backs up the chance he may hurt you again.
He must realize he has a problem before he can take any steps to fix it. He must also realize this on his own. No one will be able to do it for him. It may take several failed relationships, a friend or family member talking with him, or some other possibly traumatic event for him to realize the issue. Or he may never realize it at all.
My concern in this is that you care for yourself. If you chose to maintain contact with him, be sure to set clear rules for behavior that is allowed and not allowed. For example, if the conversation starts to become abusive, you will hang up immediately. This will protect you from becoming emotionally abused by him again.
Also, you may want to start dating other people. He has moved on and you may need to as well. If you have other healthier relationships to compare this one to, it will be easier for you to move forward.
There is a book you may want to read called The Verbally Abusive Relationship: How to recognize it and how to respond by ***** *****. It is found on Amazon.com or your local library may have a copy. It will help you gain insight into your relationship with your ex and help you find ways to cope.
Remember, let yourself mourn this relationship but also seek out healthier relationships and find ways to care for yourself. You deserve to be treated with respect.
I hope this has helped you,