Why spouse would lie constantly?

if you were cheating on your spouse...would you tell them?!?! "Honey I'm cheating on you," says he/she. Doesn't sound good!

So they don't get caught and yelled at! duh!

People lie to protect themselves. People lie to protect those they care about. People lie to keep from losing a person or things they would rather keep. People lie because it's easier than dealing with the truth.

both answers are true and valid...even though I put the first answer