Why do me and my boyfriend have the same things that happen to us?

Like last night we were together,but before that wevhad both of our friends lie to us!he asked wht friend was doing and she said a sweet 16 but then she posts pictures up on fb of her and her friends snd my bf ex and her bf on the beach!..then my friend lied to me to saying she couldnt hangout but meanwhile she hung out with her other friend and posts on fb! She could have told me the truth! Like ppl r sooo fake sometimes..but why did our friends do this?and why did this happen at the same time..?