He’s also my business partner. He kept his watch collection with me since his wife doesn’t allow him to buy watches and made me promise not to ever tell his wife about them. Not only because she doesn’t like it but also because she will definitely ask him to sell them and probably spend the money on clothes and traveling like she often does.
He lets me use the watches in the condition that I don’t cause any damage. But now that he passed away it doesn’t feel right any more.
His watch collection is worth about 200K$ in todays market. I think the lawful and ethical thing to do is to break the promise and tell his wife but I’m not sure that’s the right thing to do since he made me promise not to tell her.
Control and ownership are two completely different thing. OP certainly had control of the watches but control does not necessarily imply ownership. If the watches were acquired while the friend was married, they are technically jointly owned, even if the wife doesn’t know about them. And if the watches were acquired pre-marriage, ownership would mostly likely be transferred to the widow anyways. By not saying anything you are depriving the widow of making a claim to the property - property that most likely already belongs to her. There maybe some obscure rule that allows you to keep them, but making a ruling on such is the job of a probable court.
Simply put, you have both a moral and legal responsibility to turn over the watches.