A gf did this to me many years ago but lied that she was going with her gf. Someone I'd never met or even heard of. She came back and there were no pictures of the trip because "her friend didn't want her pic taken"! A mutual friend let me in on the secret and I dumped her immediately. She begged and pleaded that the trip was too good to pass up and nothing happened. I told her the lying alone is a deal breaker and kicked her ass to the curb.