Is it better to lie than break a relation?

Couples may believe that being honest can up the happiness quotient in their relationship, but at times, it may leave them only to regret their decision. Sometimes it's better to lie, at least if it helps saving your relationship. While keeping secrets at times is harmful for the future of a relationship, 'white lies' are supposedly believed to be harmless and help sustain a long standing relationship. In situations where the 'truth' might put your better half in an embarrassing situation, it's a safe bet to rather opt for a white lie that not only puts a smile on their face, but also protects your relation from misunderstandings. Are white lies safe for a relationship? Or are they harmful for the growth of trust in a relationship?