From your posts, you're very self-aware, insightful, and working so hard on your therapy. You're not a mental case!

You can be unready emotionally for a relationship. Many people are, at different points in their lives. That doesn't mean you're unwell, or somehow permanently broken in the relationship department.

Just switch out your language for a while. Replace "mentally unfit" with "emotionally unready."

You're taking steps to become ready to be with someone else. Eventually you will be