I haven't read in depth all of the posts here but just my first impulse is to say that likely a a 47 yr old man is not going to be easily changed, unless by his own volition.

Without making any judgments whatsoever on his and his parents relatsionship with him the thing to consider is this: do you see yourself accepting the way things are now or would you expect it to change in order for the relationship to continue? Because likely this will not change in the near future or quite possibly, ever.

you do not see yourself as number one and you should be as a mate to someone.

It's up to you whether you want to accept how it is and remain in the relationship but you sound quite unhappy and frankly I think moving on like some have said here is what I would personally do.