Some people sabotage their happiness. When things are going very well for them, they find a way to create a problem so they can be unhappy. They feel that they do not deserve to be happy.
When they go back to their unhappy ways, they blame others for it. It could an issue of lack of self-esteem, low confidence, or conditioning. It is hard to help these people because often, they do not want to receive help.
This situation can arise at work or at home. In both cases cutting the ties will not be easy. If you can build trust with the individual and inspire them to be objective, things may change gradually.
In some situations that not be the case. If that is the situation then don’t take it personally. Some people are happy to be unhappy!