So surprise to me but my SO had another girl take my place at the event we were suppose to go to…

So surprise to me but my SO had another girl take my place at the event we were suppose to go to together. When he kept telling me he had nobody to take my place and it will be fine. The guy he works with wife backed out as well no big deal.....now go have fun with friends....BUT ladies this is a girl only he is friends with and me and her dont communicate at all. And hr has said out loud multiple times how attractive she is/nice body And he didnt even tell me til after he got home half hour ago.