Of course, no relationship is perfect. In fact, disagreements and fights are a part of every healthy equation. As is temptation toward other people, and difference of opinion, and those little white lies. But, there's a line which should not be crossed, because what lies on the other side is unacceptable.
A relationship is about compromising, and finding the middle ground, but not when it comes to these five things:
Little white lies are okay. But, lying about things that matter, like one's whereabouts, social circle, and finances, is not okay under any circumstances. A relationship is based on trust, and lying severs it irreparably.