Hugs and kisses to you, my dear.
I am going through something very similar this week also. I went to a mediator with my former husband, who also has a history of abuse, alcohol, neglect, etc. I followed all the advice...documented everything, etc. But it didn't matter. The mediator said it was "in the past" and that we have to look forward to tomorrow.
I have been going through the same issues as you...and I know it must help to hear that because hearing that from other mommies helps me a great deal.
Something my sister told me when I first left a year ago is something that still gives me strength. That is that you are still the mommy. No matter if your sweet child goes with dad, if you are a loving and constant nurturing presence in your child's life, you are still the mommy. Even if it still means your breastfeeding patterns are disrupted a bit or a great deal. Even if you don't get to have special Sunday dinners every week. Even if..........
You are still the mommy and you and your child will still maintain your sense of family if that is your goal.
I used to get very sad thinking how different my son's life would be as a 'child of divorce' but I don't think about that anymore. Because every child has a different reality. There are children in married homes with miserable daily realities. There are children in single parent homes with wonderful daily realities. And vice versa and all the way around.
Of course, our life is not what I dreamed it would be. But I am determined to give my son the perfect life. Support, Love, Cherish, Discipline. Everything.
If you concentrate on enjoying life one day at a time, it will be smoother, I do promise that. That's what helps me get through times when it seems like my lifetime is ruined. It is not. And neither is yours.
Peace, love, and strength to you!