You have every right to feel angry, hurt, disillusioned, and discouraged. This is seriously hard to deal with even on the best of days, and attachment (especially a broken attachment) is the perfect accelerant.

That said, sometimes people don’t mix well together. Someone can be with one person and have it not work, yet be totally fine with someone else. It doesn’t necessarily mean anyone is better or worse, just that it wasn’t the right combination for it to work. But I understand why you feel like it’s all and only you. I felt the same way for a long time - and some of it was me, because I was untreated, but not all of it.

The treatment(s) can take a long time to really show/help, and not every treatment will work for you. DBT helps a lot of people, but it doesn’t work for everyone. Sometimes schema therapy is better, or some other variety. Therapists have their own issues and can take it out on us when we frustrate and/or defeat them. Especially the ones that are one-trick ponies. Don’t give up, even though it’s hard. You deserve to be happy (happier) and whole.