If it helps any, I had/have a similar situation with the female I raised as a lone duckling.
She slept on us and loved to be picked up, fussed and fretted over.
But as time went by she hit the awkward teen stage (at about 14weeks) - then wanted nothing to do with mum and dad; it was too embarassing to be seen with us apparently!
She got over this after a few weeks. It was horrible at first but ducks grow so fast that it was over before we knew it.
Things aren't the same as before though; she's an adult duck now, so she expects a little respect!
Holding is tolerated but she won't be happy about it when you put her down (huff is the best term

).
Stroking is ok if she has initiated by grooming me or by peeping at me almost like a duckling.
She still likes to follow me round and sit on my lap when she can too.
The aggression started in the teen phase too - so his age may well be your issue. It was mainly food possesive behaviour in my case - she was living outside with her new friends at that point tho; so she took the territorial disputes to them instead (2 campbells twice her size and a bunch of chickens!).
Be warned though; to this day there are times when my little princess kicks off at old daddy, and must she have her own way! The clue is in the statement there - my partner and I made a rod for our own backs by doting on her so much when she was younger; we created a little monster! She considers us her equal at best and all other fowl are her minions who must fear her and with whom she won't share the toys (except for her 2 daughters who get away with murder!)
So you probably have the equivalent of a spoiled little princess, that's right, a spoiled little brat
I don't know what to say, other than that there are times I could strangle my darling duck; but I wouldn't change her for the world all the same!
Good luck, tho I fear it's already too late for that