Does this count as cheating?

Ok so basically my boyfriend went abroad to do charity work (somewhere in Africa) I think! While he was there he got "married" to another girl as a "joke" even tho it included a kiss on the cheek etc... what hurt is I found out through a friend who saw pics on Facebook (I'm not even mentioned in ANYTHING on Facebook) I'm not the jealous type but it really upset me! People even think they're in a relationship:( am I being stupid?

Update: it was another girl on the same charity job

Update 2: thanks, I already knew that but just wanted to check I wasn't just being jealous!

Update 3: I do know what country he's in I just didn't see its relevance. Also, I do pay attention to him :)