Everyone is unique, and there is no rule-book for post-divorce behaviour. Friends will need to be guided by newly divorced couples, and resist any judgements about the appropriateness of their behaviour.
Some couples manage to put the anger, pain and resentment behind them and forge a calm and mutually supportive relationship. They have found ways to banish blame and reproach, and have probably re-discovered some of the compatibilities that brought them together in the first place. This is good for the children, though potentially confusing - if mummy and daddy get on so well together why aren't they still married?
Nevertheless, the behaviour of couples who manage to re-bond is very civilised. It poses little strain on friends and family and minimises the impact zone of the divorce.
Unfortunately, many divorced people are overwhelmed by disillusion, anger, blame and resentment. The simple truth is that these emotions are extremely disruptive and distressing when displayed to children, family and friends. Many people socialise at a fairly superficial level and find sudden revelations of profound and destructive emotions highly embarrassing. If you are newly divorced and gripped by negative feelings, therefore, be very discerning about displaying them in public, and don't confide primal emotions to mere acquaintances.
Most people have friends and confidantes who they can trust, and it is wise to entrust them with your feelings of anger and bitterness. Even though it is an immense effort, exercise self-control when out in public, be calm and non-committal about your feelings, and never speak negatively about your ex. Long tales about legal battles, dastardly financial dealings and flaming rows will soon have you struck off the dinner-party guest list, unless told with humour and self-deprecation.
Your family and friends, if they have any imagination, will have some inkling of what you are going through, and will admire your stoical good behaviour.