Why does she need my company's equipment?

Both my wife and I are working from home.  I'm a phone rep with my job and she's not with hers.  For the past year I have had my entire workstation in our bedroom taking calls and dealing with patient's and doctor's offices.  My wife works in the accounting dept on her job.  No phone calls whatsoever.  Well, yesterday my job sent me a new desk phone and headset to set up because I was having issues with my phone.  I set everything up this morning and started working.  My old equipment was sitting on our bed.  She walks into the bedroom and asks me if I have to send the stuff back.  I told her no I didn't have to send it back but I'll just take everything  back when we go back into the building.  No telling when that will be.  She picks up my headset and asks me if she could have that.  I looked at her and said no.  Then she got an attitude about it.  It's one of those Plantronics headsets but my workstation has the hookups for a phone and headset, hers does not.  Again, she doesn't even take calls nor does she make them.  Why did she get an attitude when I told her she couldn't just use my company's equipment for her own use?  She must have though it was mine to keep.  It wasn't.