I have heard a lot of people say this. They are better if they aren't together everyday.
I know someone who's hubby works in a different state and only comes home on the weekends. They actually split up for a while because they were together to much. When they realized they are fine if apart more, they got back together.
Dh and i on the other hand love to be together all the time. We do enjoy getting out with friends, but we also have no problem being just us most of the time. I couldn't imagine being married to someone i couldn't be around everyday.