Reading through the pages, I found some tips on how to detect if someone is lying to you by just observing the body language. Take note though that these tips are only applicable to somebody you know well enough.
So here are some ways how to determine if someone close to you or you know well is actually lying:
1. Forced smiles.
Real smiles involve the muscles around the eyes.
2. Formal phrasing.
Eschewing contractions such as "don't" and "can't".
3. Vocal pitch changes.
Non-lying vocal levels are relatively even.
4. Erratic eye contact.
Truth tellers maintain contact, occasionally looking up and to the left while liars look down and to the left.
I personally not sure with the second item but the first, third and the fourth are quite helpful.
So, there you are folks, be vigilant. You can practice with your spouses this Valentine's Day.