It is weird to me too, I think people should stop thinking that marriage is a must. You can survive without getting married and even have a better life compared to someone who is in a toxic or messed up marriage. For example those women who get married as the third or second wife. You can't be happy living in such a marriage or family since you won't feel the affection from your partner.
The fact there are failed marriages does not mean that there are no wonderful marriages. Furthermore, it is not automatic that the children will follow the same path of life as their parents. People want different things. There are those who enjoy companionship while others want a totally independent life. A child from a broken home may want to have a married life and they should be given all the support needed to make it a success. Generally, parents want their children to have a much better life than theirs. In this instance a parent must be open and admit to their children the mistakes they made in their marriages so that the children do not repeat the same mistakes. Furthermore they must emphasize to their children that a good marriage begins by getting married for the right reasons.
In summary, I can say that divorced parents know that it is possible for marriages to work and the fact they themselves failed in this regard does not in any way mean that their children's marriages are cursed and doomed to fail.