It’s easy to find things that are wrong in any given situation, and yet at times it can be so difficult to find the things that are right. Despite this, you should not feel that punishing your ex is the best thing to do.
Punishing them with negative comments or saying nasty things about them to the children, will have a negative impact on your relationship with your ex and your children. Remember children love both their mum and dad and know that they are half their mum and half their dad. By punishing your ex and speaking badly about them, you are at the same time speaking badly about the children.
Through your children, your ex may be part of your life for some time following separation, and it is best if you are able to co-parent with them effectively. Your ability to do this may be impacted by your conduct at the time of separation.