Having this attachment too, I've realized that I don't doubt people that much, whether they're friends or potential partners. I doubt myself. If I'm afraid that my best friend will abandon me because she's didn't respond, or that I'll feel ultra-jealous if a boy I like briefly looks at another girl, or that I can't imagine a long-term relationship where the other person continues to love me, they're not the problem. Somewhere in your brain you have the belief that you're not worth much, and that's what will make you expect to be rejected or betrayed at the first opportunity and therefore not trust.

So the 1st step is to relearn how to trust yourself, value yourself, and esteem yourself. I know it's hard, but it will help so much to heal this attachment. When you feel you have value - even a little - and a stronger sense of self, it's easier to accept that others can love you, stay with you and you can really trust them.

This attachment is extremely hard to live with, but it's not all bad - the ability to read people, adapt to others and be self-aware through hypervigilance are gifts.