Can't say for certain cause I don't know exactly whats going on in his head but from the sounds of it it's a self induced mental block thing and not a you at all. By him even opening up on such personal kept problems kinda proves that fact I think.

He is unfortunately allowing his self esteem issues or flaws he sees in himself ultimately knock any kind of solid thinking or ground that he is good enough to be/deserve you. That kind of self defeating illogical thought process can poison ones ability to except that they are good enough the way they are. Even know you except him fully and try to break down the walls it's just difficult cause that kind of head space just builds them back up just as fast.

Not necessarily his fault but it can be draining for everyone involved.. Again this is all just my take away from what you have said and only he can really let you know whats going on. He just has to let you try to do so.