What to do?

My husband and I have had some trouble in our relationship, so much that we are legally separated but we are trying to make it work for our kids. Well recently I have been getting headaches every time I see him or even talk to him on the phone. I don't know why. Even if we are not arguing I will still get one. I don't really know what to do and doctor says I am healthy and everything is normal. I can't keep getting headaches though, it is impairing my everyday activities. What should I do?