Your problems have solutions. It sounds like these mistakes were repeated and clear. It seems that you could intellectually see it, but you chose differently for other reasons. It may be an emotional barrier. Do people consider you stubborn? If so, that's fixable. Stop. You don't have to brain up, you have to wise up. The thing in your way is you and your brain but not in the way you're expecting; it's not intellect but wisdom. And it's not going to be fixed with brain surgery or an increase in IQ. It's going to stop when you allow it to stop.

People think of Therapists as Surgeons, a last resort. But they're also General Practitioners that you can just talk to. It can be that external help/voice. I really suggest trying for a couple months and see if it offers you anything. No harm if not. Or don't -- that's ok too. But they can't do shit unless you try.

Try the two other things I mentioned: long walks and wild writing. Again, try it for two or three months. If it doesn't help, no harm.

The key to this is in your hand. But it may not fit the lock that you're expecting. If you're open to true change, you can be pleasantly surprised but first you have to try.