We must remember that grievances are different, and that some of them are just basically will not work. In this case, you will need as soon as possible to erase the former husband of his life, or, if not possible, to change their attitude to it, starting to treat him formally, as a colleague. Gradually, you will begin to calm down, and people will go into the category of friends, conflicts with that not so offensive as with loved ones.
Often grievances can live for a long time in my head. The woman does not want to let them go, considering them their trump card in case of conflict. Small, with no special importance is best to let go of resentment at once, otherwise you risk to accumulate in your head a ball, which in the future will be very difficult to handle. Using the facts that you once offended when a frank conversation with her ex-husband is unlikely to help you, but rather, on the contrary, will worsen the relationship between you.
When a woman is holding a very long time in my head all the problems associated with ex-husband, it forms the so-called "enemy image", and subsequently begins to consider the former chosen enemy. It is best to first try to understand yourself and find out whether you deliberately hurt or you are trying to shift the blame for the collapse of the relationship to another person. Try to erase from his life along with all the negative things that you associate with it. So it will be easier to forget about the past, and questions about the reasons for your divorce, you can easily answer that did not get along and not look for the answers. These responses do not play any role for you, because you're starting a new life.