Idealisation of parental figure and internalising the primary care giver is quite a normal phenomenon in development of any person. From what you are describing, it seems this has gone too far and is causing significant inter personal problems between you two.

The first thing to do, I suggest, is for you to talk to him about this. This would not only start getting the process of getting help but also will let you know his reaction to getting help. Any kind of help offered will obviously work with the hard work of the actual people involved and hence this is very important.

Inter-personal therapy appears to be a good form of talking therapy for you too but before anythign of this sort is sought out, please have a preliminary assessment by a mental health professional to see if there is any need for you both to seek help or is it that it may be you that may be overly sensitive. Sorry fro suggesting this but a competent professional has to look at all angles of a problem.

GoodLuck

why just speaking mode? may be making it a writing mode helps. make him pour out his heart in love letters if he can. or inference from movies that he likes or whatever.....but finally there is a limit to inference....so what about showing this conversation to him?

I know u must have tried all this but....that is the only way to go.

from your point of view may be u need a break from him also? why not take what is called a respite break from him?

professionals may suggest lot more

goodluck