If witness my boyfriend lie to others, how cautious should I be?

I have been dating a guy for about a year and I have witnessed him lied to his best friend and family members. Everytime he mentions that he going out this his co-workers, I become suspcious, wondering if he is just lying to me. I understand that no one is perfect and that we all lie at times. But I am young and I refuse to make time for depection. Am I making a big deal out of nothing or is this something I need to confront?