DH won’t tell me Amazon Prime password

[VashtaNerada]

So we have Amazon Prime which means we get free next day delivery. I generally just ask DH to order stuff but he often gets the wrong thing so I asked for the login details and he has point blank refused! We have a shared bank account so pay for it together but he claims it’s ‘his’ account and sharing details isn’t appropriate. What could he be up to?
I’m in two minds over this. Part of me is imagining gifts for another woman. But he grew up with fairly dysfunctional parents (who later divorced) who did all kinds of odd things he seems to think is normal, secrecy being one of them. For example he hates taking money from my purse if I ask him because he sees that as my personal space, even though I 100% trust him to take the money and nothing else.
Anyone else’s DH act like this? Am I being hopelessly naive in thinking it’s just a peculiar quirk? Or does anyone else think he’s right not to share his login details?

We've got our own completely separate amazon accounts both linked to dp's prime.
No sharing of payment methods or details at all.

I can’t believe how many people have said they use the same passwords for multiple accounts. That’s a hackers dream.

I wouldn’t share a Prime password with anyone, although if they sent me the link and the address to send to and they can send the money for it before I buy it then I’ll do that.

Maybe yes, maybe no.

But he was up to mischief. Odd that.

Does he have a personal account too? Because if it's just the joint account he can't be hiding purchases as you'd be able to see them on the bank statement.

DH does have access to the same amazon account but he only uses it for buying stuff. We both use it for TV but that's on the family TV or my iPad. But I'm always secretly glad he doesn't really use the kindle app as I think I'd be embarrassed if he saw my Kindle collection! He theoretically knows how much crap I read, but if he actually saw it I'd worry he would think he'd actually married a much less intelligent and well rounded woman than he thought he had! .

I have a pact with a friend to open and delete all kindle books on our phones/ kindles/ iPads if either of us dies unexpectedly to avoid post-death embarrassment. only slightly is this a joke