Ahhhhhhhhhhh......first, I want to say, I HATE WHEN PEOPLE SAY "This too shall pass" ...biggest pet peeves ever! Stfu, I know it'll pass... ugh.
I have been dealing with lying my entire son's life. And now that he is (almost) an adult. His lying now, only affects his own life, so he's learning on his own. I realized he lied, because of the way I responded to him. They lie because....perhaps they know you will be disappointed? They lie, because they know you'll yell? They lie because you don't respond enough (get away with it)? They lie because they are testing their strengths and intelligence....Liars are smart people. They lie because, you lie?! All sorts of reasons. It's important to not make too much drama over it.
Try not to react. Try very hard and let natural consequence take place?! I know it worries you....don't let it. Just don't react poorly. If they lie about something that hurts someone else, then they need to understand that is wrong but try not to make too big a deal. This is where they need to know love for others. and yup, I'm going to say it......if you are raising them correctly, this will pass.
Be sure YOU AND YOUR HUSBAND do not make up anything. Make sure everything you say is as truthful as you can. You have a smarty pants on your hands that will pick up on all of this.
That's all I got~ Parenting aint easy~