Wife or Mistress
The architect, the artist and the engineer were discussing whether it was better to have a wife or a mistress.
The architect said he enjoyed time with his wife, building a solid foundation for an enduring relationship.
The artist said he enjoyed time with his mistress, because of the passion and mystery he found there.
The engineer said "I like both"
Engineer: "Yeah. If you have a wife and a mistress, they will both assume you are spending time with the other woman, and you can go into the lab and get some work done."