Would you like a lie with that?

When lying becomes a chore, does it mean I'm growing up?
Possibly not. To be honest it just probably means that you've done it so often that it has become something tedious and overrated.
But when, in friendships and relationships is it okay to lie to the other person or other people?
They say that;
             "The best recipe to ruin a relationship, is for everyone to know about it,"
but is this correct? Could it be possible to be 'involved' with someone without people knowing  about it and it being successful- or is it possible that people will start to figure things out? Will the lies become so deep that to get out of it would be a release of the noose around your neck?

Understandably when in a committed relationship there are reasons for truths to be withheld, but where in the rule book of relationships does it say that lying can't be healthy? What happens if what the other person is lying about is to help protect the one that they're involved with. Selfish or do gooder, the line between good and evil blur together often enough to confuse the best of us.
Cheating is one of the lies that you keep from the other partner purposely to not hurt the feelings of the one that is getting cheated on, however is that the same as protection of the other person, you or both?

When it comes to lying there are hidden motifs, trapdoors and bogie-traps hidden under every undercurrent of your voice, the blinking of your eyelashes or the deep inhalation you take before the lies start rolling off your tongue. Lying can be healthy to those doing the lying, (at times), but remember fellow liars. Sometimes the lie you ensue, isn't worth the consequences.