ADVICE NEEDED : Husbands crazy ex

Brooke
My husband has two kids with his ex girlfriend and she is crazy. A little background on their relationship. She got pregnant with their first son and a few months later, kidnapped their son and moved to Wisconsin. She played games and threatened him with custody because they weren't married. He was devastated and did anything/everything just to get his son back. He begged her to move back and live with him and she eventually agreed. She had zero ambition to get a job or support the family and he got tired of dealing with her so he allowed her to be a stay at home Mom. He said he stayed with her because of the child and was worried about losing him. She got pregnant again but lost it during delivery. It was a rough time for him and he didn't feel like he could leave her after everything that happened. He had been looking at apartments and moving out but then found out she was pregnant again. He wanted to help her and see her through the pregnancy which he did and she delivered last dec. Once the baby was born, he got his own place and moved out.  Two months later I met my husband and we instantly clicked, we were married within 6 months. When she found out about me she tried to get me fired from my job, physically assaulted me in my husbands truck after running into her at Walgreens....
Since he has moved out she has used the kids as tools to hurt him, limiting and controlling his time with them. He's basically her puppet until court is established and it's taking FOREVER! It's difficult for me to watch him give in to her every request and accommodate her because she is not a good person. She recently wanted to meet and talk about the "kids" but It turned into hashing out their relationship and what went wrong. I told him I didn't think the meeting was a good idea because she always has an alternative motive but I supported him because i thought it was about the kids. He used to tell me everything they talked about and what was going on but I feel like he is so frustrated with everything and her that he has just shut down. I question why they need to meet, why can't things be talked about over the phone? When I ask questions or voice my opinion on things, he says it's none of my business and if he wants to keep that part of his life private he should be allowed too. Am I wrong to want to know what they are talking about and what's going on? I'm finding myself feeling insecure about their relationship.