The CPS should contact you before the trial date is set to check your availability.
In answer to your second point I would not advise that you simply fail to attend. If the CPS has asked you to attend it is unlikely that they will discontinue the proceedings if you fail to do so and will in all probability request that a witness summons be issued. There really is no point in messing the court about.
You have not given any details of the incident but as I said earlier I assume it is one involving domestic violence. The reason for the CPS taking a robust stance in these matters is that huge amounts of police, CPS and court time is spent on cases where the alleged victim provides a withdrawal statement soon after proceedings begin. Apart from the costs involved, almost always this means that offenders are escaping proper justice. Once again, this is not a matter for you to decide and you should co-operate with the CPS.