I think that you are mixing 2 things that don't go together:
1. being positive
2. Your Dh.
I'm sure that your DH has many wonderful qualities, this just isn't one of them. Since you are using LoA, use it ON him. Make a list of his wonderful traits, and then focus on those. Take your focus off his short comings (we all have them).
Next, do other things besides talk to him to work on your LoA stuff. I like to journal. You can also post here, talk to your friends etc. For now, just leave him out of it.
There are zillions of resources on LoA, but my very, very favorite one is "Ask and It Is Given" by Ester and Jerry Hicks. What is so great about this book is that the last half is Processes you can use to change your vibration. It's like little games to play to work on manifesting. None of them require getting your DH on board!
One of my favorite is called "The Creative Workshop" and it's a journaling exercise. You write down short list of what you desire, and then go back and write down WHY you want those things.
I want full custody of my son because..
and just write down what comes to mind.
"When you think about why you want something, you usually soften resistance, but when you think about when it will come to you or how it will come or who will help it to come, you often add resisitance."