An architect, an artist and a scientist were discussing whether it
was better to spend time with the wife or a mistress.

The architect said I enjoy time with my spouse, building a solid
foundation for an enduring relationship.

The artist said I enjoy  time with my lover, because of the
passion and mystery I find there.

The scientist said, "I like both."

"Both?" they asked.

Scientist: "Yeah.  If you have a spouse and a lover, they will each
assume you are spending time with the other, and then you can go
to the lab and get some work done."