Some time back, a Mr. Johnson wrote a post asserting that it is always sinful for individuals to affirm in speech or action something they believe to be false (I’m using Grudem’s definition here, who believes all lying is sinful but not all deceit). Johnson took his mower to the whole field of lying and in one swath condemned any kind of untruth. My good friend Seth generally agreed with him and took his place in the passenger seat, along with John Murray and Augustine in the back. Interestingly, Johnson first quotes the genre of general principles for his dogmatism (Prov. 6:16). His final conclusion he calls “simple”.
But hold your combine just a minute. Peter encourages us in 1 Peter 3:10: “Let him keep his tongue from evil and his lips from speaking deceit”, a direct quote from Ps. 34:13. The heading of this psalm says: “Of David, when he changed his behavior before Abimelech, so that he drove him out, and he went away.”
So David could not have thought of his deceiving act of madness before the king of Gath in the same category as sinful deceit in v. 13. Thus, it’s not that simple. An ESV note for this chapter says David does not “deny the importance of the faithful using of wits in desperate situations.” Perhaps “does this make me look fat” questions from our wives count as desperate situations.
Which leads to Seth’s astute observation: should we be able to lie to our wives so we don’t hurt their feelings? Okay.
Suppose I’m counseling a couple who also happen to be friends with my wife. In our conversation the wife is Jezbellian in her rudeness to me. I know my shoulders are broad enough to carry this offense and that my wife, as the weaker vessel in this regard, will be tempted to retaliate Ahab-style when we meet together as couples later that month. So when the missus asks me how our time went, I say: “It went fine”.
Isn’t this wisdom, an effort to live with my wife “in an understanding way”, as the apostle says in 1 Peter 3:7 just a few verses before the deceit passage? Doesn’t this kind of withholding of truth belong in the same milieu where deceit is legitimate, such as parables, war, and the flea-flicker? Of course husbands should model truthfulness, should not consistently keep their wives in the dark, and should make grand efforts to inform them of their highs and lows.
But is this the case every time? Is this situation to be viewed as sinfully deceitful? I don’t think so.
Between Two Cultures 
I don’t think David’s success (or rather, the lack of any recorded consequences) is necessarily a sign that his little show was acceptable or not, although it certainly gives us something to think about regarding the truth and pragmatism. On one hand, dishonesty is generally pretty easy to identify, and to say “Thou shalt not” means never is a pretty good solid policy, but there are surely times when telling the truth seems like the wrong thing to do (I always think about Corrie ten Boom and her sister when this subject comes up); it may be that we are oversimplifying the issue to say a person is always sinning to not choose honesty, but that’s hard to prove from Scripture.
Regarding your example of being honest with your spouse, my husband and I have a policy about this- total open honesty. I respect him enough to handle realities that may bother him, and vice versa. I believe that if one of us ever opted to deceive the other as a protective measure, it would be in the absence of respect. If your relationship is such that she would rather not know something that would aggravate her, so be it. I think that would qualify as just living peaceably, given that you’ve both generally acknowledged this.
*As a side note, I think it would be extremely wrong to presume that your partner simply couldn’t handle the truth, but I don’t think that’s what you mean, right? I don’t mean to get off-topic, but reading “Perhaps ‘does this make me look fat’ questions from our wives count as desperate situations,” made me want to be clear on that point.