Walking, I think the two of you need to go into marriage counseling. He needs to open up to you. this may hurt but maybe he does want to leave you. Your health issues maybe getting to him. It is not your fault that you have health problems. With counseling the both of you can get this worked out. your anxiety and worry are far worse then what may really be on his mind. Takea deep breath Walking, Relax and don't let worry ruin your life. It is far better to take some action do something rather then sit and wonder and let you mind run.
Also keep posting here never mind if you think you are posting to much. We all need help and support. Post as much as you like.