A regex that doesn't accept comma or dot consecutively

1. It only allows letters including ñ and Ñ
2. doesn't allow other special character besides comma and dot
3. doesn't allow 2 consecutively dot and comma in any part of the name
4. Doesn't allow comma or dot besides each other
5. Allows space in any part of the character

What should I add to my regex?

^(?!.*[.,]{2})[a-zA-ZñÑ.,]+$