My understanding is that when you marry your possessions become joint possessions, so she's not guilty of theft as they're still married. If indeed she paid for the bulk of the wedding costs and is footing the bill for the divorce as well I don't entirely blame her for wanting some cash from the belongings he brought into the marriage. He hasn't come to collect the guitar, nor did he take it with him - the diagnosis of severe depression may indeed be the right one but there's no way of being sure of that from what's written here.

Can't help but notice the posts suggesting she's guilty of theft seem to come from male 'catters.   No sympathy for the relatively new wife, deserted by husband for no reason she can understand? Just because it's a guitar she's selling and this is a music forum?