Gwen Stefani and Blake Shelton are looking forward to some down time as they wrap the latest season of — and celebrating their first Christmas as an engaged couple.A source tells ET that while the year has been tough for everyone, «Gwen and Blake have spent a great deal of time reflecting on what they have to be thankful for.»«With their recent engagement and the holidays coming up, they truly couldn't be happier,» says ET's source.