Imagine this. Things are going great in your relationship. You two have fights here and there, but nothing that surpasses the unusual couple-y fights that normally happen in any relationship.
One night you and the significant other are hanging out, and your boyfriend mentions needing to go to his best friend's house to pick something up, and it's no big deal to you, so you leave and head home, after spending some time with him. At least you got to see him at all, right? Once you get back to your place, you get on Facebook and his best friend has posted, while you were with your boyfriend, that they're having a little party. Why didn't he just tell you the truth? Why wasn't he honest with you about something so unnecessary? You wouldn't have cared if he'd gone to party with friends. Why'd he have to lie to you about it? It was completely unnecessary. On top of everything, he asked you text him when you got home, you did. He never gets back to you all night. Your mind wanders, of course.
Little lies are told throughout a relationship, some to save face, and some just to avoid fights. Some lying is necessary while other lies like these are not. There's no point to unnecessary lies. It doesn't help but make trouble in the relationship because doubt and suspicion are opened up with these kinds of lies. According to a Reader's Digest article, men will lie for only a couple reasons: for their ego, or to conceal something. It is a big trust violation.
Questions linger when lies are told, and it makes no sense why a lie would be needed, especially in this situation. The sooner you find the truth behind these lies, and reason for these lies, you are able to fix the relationship or fix what's going on. Or at least attempt to try to.
There are people out there called compulsive liars. People who can't help but lie, and they don't even realize it. Some have more severe cases than others, of course. They may even believe the lies themselves. There are realistic mental conditions out there that involve lying, but treatment is needed to get help in any way.
Pathological liars are out there as well. This is the habit of one's lying to get one's way while not considering the feelings or rights of others. Pretty much doing whatever you want, and just trying to cover your tracks. This is different from compulsive lying in the sense that these people know they are lying and don't care, whereas compulsive liars believe the lies and will defend them and seriously believe them, not just act like they do. Pathological liars lie to benefit from something, for themselves. It is always all about them.
But, keep in mind, not everyone who lies have any of these conditions. They could just be lying for the heck of it, not because they have a condition, so don't jump to conclusions, or feel sorry for anyone yet. You've got to do your research to make sure you figure out what's going on. Talking is definitely needed, especially if this isn't the first time it's happened. Sometimes a liar is just a liar.