No one has to live with domestic violence. One in every four people in the UK suffers violence at the hands of a family member.
The most important thing is your safety. Coming between the 'abuser' and the 'abused' rarely works and is very risky. The problems that the abuser has are not just physical, and until the deeper underlying problem is resolved he or she will continue to physically abuse. The hitting and punching are a symptom of abusers' problems and they will not be able to stop doing this without the deeper problem being resolved.
If you are witnessing or being subjected to domestic violence, seek the help and support you need from your GP or one of the organisations on the Internet or with a helpline. Type 'domestic violence' into a search engine and you will see just how much support is out there.
If you have witnessed abuse within the home, this may have affected how you now react to people and situations. There are a lot of resources available to help you deal with this, and it's important to recognise that there will have been some lasting effects on you.
Always keep in mind that abuse of any form is wrong and you can change it.