Hospital called my ex-husaband of 5 years and told him about that I had ER visit and when I had it. They said he was on file as husband. Can I sue or file formal complaint?

It's not very likely. As long as your records still list him as the primary contact with rights of disclosure, they did nothing wrong. You might want to make sure his name is removed from any other hospital/doctor's office you've visited in the past.