The struggle with relationships that you describe is very common for people with borderline personality disorder (BPD). A key symptom of BPD is fear of abandonment. This symptom may cause you to need frequent reassurance that abandonment is not imminent, to go to great lengths to try to avoid abandonment and to feel devastated when someone ends a relationship with you.
But you are also describing another phenomenon that’s common in BPD. People with BPD tend to have more unstable, chaotic relationships than others, and these relationships often end prematurely due to conflict.
In many ways, it’s a double-whammy.
People with BPD both fear abandonment and have symptoms that create conflict with others and often lead to abandonment, which then reinforces the fear. In addition, people with BPD are likely particularly attuned to the experience of being abandoned. So, even though it is painful for everyone to experience the end of relationships, the end of a relationship can feel particularly devastating for people with BPD.
The good news is that there are things you can do to try to stop this cycle. For example, in dialectical behavior therapy (DBT) a set of skills called the “interpersonal effectiveness” skills are taught. These skills can help you learn to be more effective in relationships, which can make those relationships stronger and more likely to last. If you aren’t getting DBT now, this may be something to talk to your therapist about.
Schema-focused therapy also may be helpful in identifying and actively changing problematic ways of thinking that cause issues in your life. It can help you pinpoint unmet needs you have that you’ve been trying to get others to meet in an unhealthy way and find healthy ways to get those needs met instead.
In addition, it can help to explore the roots of the abandonment issues with your therapist. It sounds like you had some experiences in your early childhood that would understandably leave you afraid of people leaving you. Talking about how those early experiences influence your current ways of viewing and interacting with the world may be helpful.