For those who are suffering in a bad relationship, it is often best to end it. A breakup occurs when both partners cannot reasonably express their feelings or cannot find solutions, and it is usually one person that holds up the process. For the partner who has been subjected to passive-aggressive behaviour, they often feel pain because they never understood the issues. Lack of understanding keeps them wondering what they did wrong, and they may need professional assistance to understand.
When the passive-aggressive person leaves the relationship, they may also be hurt. Unfortunately, they may refuse to see that it was their behaviour that caused the rift in the relationship, and they will continue to blame any future partners for the same reason. This type of behaviour rewards them by placing all fault on the other person, and those who do not recognize it will not be able to correct it.
Getting past the pain for both partners will be a different process, and this is due to their separate personalities. The person who tried to deal with the behavioural issues will be left confused, but they can move on in their life. While the pain may be deep, it will be alleviated when they find a good partner. Their past will eventually fade, and it will take the pain with it as the wound heals.
For the person with this behavioural issue, they will have a more difficult road. Their lifestyle will generally force them to find a new partner, but their issue will remain the same. For them, being repeatedly left by their partner will become a normal facet of their life. Until they get a partner who forces them to honestly look at their issue, their wounds will continue to be opened again and again.