I think isolating yourself from others so that they can't hurt you is a very good reason -- you are obviously trying to protect yourself and keep yourself safe.

Maybe you could thanks and acknowledge that that is your intention -- to keep you safe -- and explain to yourself that there are other ways of being unsafe -- like hurting yourself. Explain to yourself that you don't deserve to be hurt (even though it may feel that way) and that you are a worthy and valuable person.

I also had one t who had me write a list of reasons to "wake up tomorrow" for when I was feeling bad -- I could go read it.

M