The relativity of lying
In life there are objective things and subjective things. One can lie about something objective, like a fact. Anything subjective is a matter of personal perception, and can vary in time. That is why there cannot be actual "lies" about emotions, feelings, perceptions, or personal experiences, except if there go against objective facts.
Here is an illustration. A man tells his wife that he doesn't want to go to the cinema because he is feeling tired. 10 minutes later, he is caught working on his P.C. The wife accuses him of lying about feeling tired. There is no way she will be able to prove that he did not genuinely feel tired when he said it, because fatigue is a temporary feeling. What is more, as tiredness is also a very gradual sensation. It is not black or white. There can be many different levels of tiredness, and also many different sorts. That is why it is a subjective feeling, and one cannot be lying by saying that they are tired, because there is always a possibility of being only moderately tired, or too tired for some determined activity but not others.
Here is another example. A man says he has had 10 girlfriends. When asking the girls in question if he has indeed been their boyfriend, 4 of them say no. Does that mean that the man is lying, or boasting about his experiences ? Not necessarily. The problem with relationships is that they are also very subjective. It is all a matter of definition, and in life, most people live with different definitions for the same words. As lying can only be about facts, definitions cannot be taken into account. Here is why.
For some people, a boyfriend-girlfriend relation starts at kissing, even if it only happens at one party on a single evening. For others, it requires having a committed, exclusive relationship over a minimum period of time (highly variable). Some won't call their dating partner a girl/boyfriend unless they have had sex. Others don't care as long as there are feelings. Some need actual love, or at least infatuation, to call it so. That is why, two people who had sex after a party as a one-night stand might calculate differently the numbers of romantic relationships they have had. Some will count it, others won't. It is all a matter of personal perception, or subjective feelings, and, well, defintion.
Even for supposedly clearer definitions, things are not always simple. Most people think that they can answer unambiguously the question "Are you married ?". But in fact, perceptions and definitions can also mislead us terribly. For some, being married is just a legal matter of having signed a piece of paper or not. For others, marriage can only be accomplished by a priest in front of God, and the administrative paper does not mean anything. Add to this that each country has its own laws regarding marriage, and each religion its own customs and acceptances. That is how too people of different countries and cultures might both claim that they are married, while in the other's eye they are definitely not.
If two homosexuals married on paper in the Netherlands meet a fundamentalist Christian for whom a a religious marriage is a must, and who comes from a US state where homosexual marriage are illegal, it goes without saying that this American person will not recognise the gay couple as being married. That does not mean they are lying, even if their marriage is not recognised either by law or religion in the place where they are. Should they tell the American guy in question that they are not married, they would not be lying to him their status does not match his own definition of marriage. So whatever they say, they are not lying. It just depends whether they take their own definition, or the other person's definition into account in the process of their communication. Some people naturally take the other person's point of view, while others stubbornly refuse to do so.
I hope these few examples demonstates well enough how it is so-to-say impossible to really lie about anything subjective.