WTBH-
Oh boy do I get this! I don't have an answer for it yet myself but this is what I am in the middle of working on in my therapy.
Part of it for me is a fear that I won't be able to "get out of it." By it I mean a relationship. I am afraid of being vulnerable because I have not done a great job of getting out of my relationship with my ex that got me here, but friendships too.
Part of it too is a fear of something good. I know that and I know it is important but it is something really hard for me to lean towards.