It's easy for your kids to diminish your predecessors when they visit. He is one of the common things, and it is natural that his life will be interesting. However, there are things you should not confuse when talking to your children, as they can cause a lot of harm and embarrassment.
First of all, if you hate the former, your children do not need to listen. They already know that you do not have the other parent. After all, you no longer live with them, and if you and their other parents go together, you will still be widespread.
Have you not considered child support? Your children do not know if you pay too much. They can not do anything that the fees will hardly leave you to survive. They do not know that their mother spends the money, and neither is it necessary. If you express your dissatisfaction with payments, you only deceive them into situations that have not been created and can not do anything.
There are other topics you can mention about the other parent. It is noteworthy to ask about their health and if they have a good time in their vacation. Nevertheless, do not expect your children to report about your previous love life. Even if they know she is sleeping with a new person or simply gets acquainted with the neighbor, she has asked your children that they are unfair. Best of all, they betray their other parents and you encourage them to do so. At least, you will probably get inaccurate information.
The children want to love you two. It is difficult to do so when they realize that it is obvious that each one of you wants to harm the other. They are vulnerable to attempts to deceive them. Even if they know that they betray the trust of the other parent through dissemination of information, they will do so because they are afraid of losing your approval. This is a very unpleasant position, and eventually they will understand what you do and lose respect for you. They are greatly respected. Keep your questions on school and activity topics and let your children be children, and they can. They can not appreciate your tolerance in the past, but when they grow, they will be grateful. After all, they do not do the rules, but they know if they are just.