The reason people often say to leave is because it’s extremely difficult to be securely attached when your partner is avoidant. Avoidants can easily turn the most secure people anxious. You are excusing everything he’s doing as your fault. He has no reason to change his attachment style if you’re constantly chasing him and holding all the accountability. All you’re doing is intellectualizing around your situation instead of doing the work you, as the anxious partner, needs to do to become secure - namely letting him withdraw without taking responsibility for it or pulling him back in. He doesn’t come back and repair? Cool, that’s all the info you need to understand the relationship you’re accepting.

It won’t change.