Self-sabotaging (relationships, jobs, etc.) is a fairly common habit of people with borderline personality disorder (BPD). Personally, I think I sabotage myself without even knowing it, mainly because I feel like I don’t deserve anything good in my life. When things are going well, my anxiety actually increases, because I’m afraid things will fall apart at any second. I’m not used to stability — it’s a foreign concept to me — so it makes me feel uncertain and suspicious.
I will subconsciously try to sabotage my relationships, because I am terrified and paranoid the other person is going to hurt me, and I tell myself I’d rather force them to leave me on my terms and be alone than live with the torment of having them leave me because they wanted to. Basically, my mindset is “reject them before they can reject you.”
Of course, I don’t actually want to end things at all, but I literally cannot cope with being hurt, the pain is physically unbearable, so I’m just trying to protect myself at all costs. People with BPD develop a lot of defense mechanisms like this to help them cope. Everything I do is a way of protecting myself somehow. I know you have to let yourself be vulnerable in a relationship, but I can’t afford to do that — the risk is too great.
So, I continue to push people away so they can’t hurt me, or as a test to see how much they really care about me. Obviously, this behavior really will drive some people away, so it’s a self-fulfilling prophecy. I’ll then indulge my confirmation bias and tell myself, “I told you so, you’re unlovable,” and the vicious cycle starts all over again.