Boyfriend cheating?

My sister in law saw a snapchat on my boyfriends best friends story.. In the background she saw my boyfriend kissing on a girl. And then my friend messaged me saying she saw on my boyfriends story, him kissing a girl. (He has me blocked from his story) he claims in not blocked and that he was not kissing that girl that he doesn't even know her. I didn't see the snap but the girls claim they replayed it many times to make sure it was him. When they tried showing me.. He had already taken them down. 

Vote below to see results!