does anyone else have abandonment issues? Are they actually possible to overcome?

most of my life I've kept people at bay, and so when they leave me, i dont much care.

however i got sucked into the attachment aspect of therapy and i am finding myself terrified at the closeness feeling but even worse at the idea of him leaving my life sometime, and it could be years away

he wants to work through it but i was just wondering if its even possible to do so?
right now i just wanna run away and push him out of my life