How strange Nae! Does the voice sound like your DH at the time you hear it? Maybe something/someone is just being a nuisance? We used to live in an "interesting" house and I would hear my mum or stepdad talking in the kitchen when I thought they were out. I'd go out to investigate and they definitely weren't home. Something used to imitate their voices, never found out what it was. Oh and we used to see a small black and white dog! There were lots of other weird happenings too. My mum, sister and I all saw or experienced this. It all stopped when we moved house.

Sorry I have no answers, just wanted to let you know that I don't think you're nuts LOL!