How can Charles be head of the church if he married a divorcee?

As the head of the Anglican Church, Queen Elizabeth couldn't attend Charles and Camilla's wedding because Camilla is a divorcee (since Diana died, Charles is considered to be a widower, not a divorcee). How can Charles become head of the church (when he becomes king) if he's married to a divorcee? Are they hoping her ex will have passed away by then, technically making her a widow?