Ten tools to communicating with your ex.:

1. Use I statement.
2. Turn complaints into requests.
3. Attack the problem, not the person.
4. Offer suggestions, not solution
5. Turn up you listening skills.
6. Avoid bad words.
7. Be respectful.
8. Keep you cool.
9. Use disarming tools, listen and do not attack.
10. Use negotiating for your own needs.

Learning good communication takes time and practice.  Try one or two tools at a time of need.