hmm.... Why would she ask you that question? That's weird.... but probably you could because if she knows your private key she should be able to access to your account.
We all need to have that conversation with our significant other and I think that talking about mortality is a therapeutic thing and a necessary thing that you couples need to talk at. For me, if I was to have that dilemma, probably a hardware wallet will be enough to suffice or you can do what Hal Finney did, he gave bitcoin to his kids.