I don't know what to think

So I have been seeing someone, long distance, for about half of year. I have have known her for about 4 years. We have been pretty serious. We say I love you, I miss you etc. we try to communicate as much as much as we can because we feel it's very important in a relationship. Well, recently she tells me that she sent a video (I don't know what video) to several girls she knows. And someone she used to mess with commented on this video and they were going back and forth with each other about the video and what this girl did that day. Then all of a sudden this girl sends her a message of her nude boobs. How does she tell me? Well first she makes a comment and says to me: "why can't some people respect other people that are in a relationship with someone, right? Smh jeeze I'm just saying here." When I asked her what happened, she said nothing. When I pressed her about the issue like you sure? She says ok.. then tells me what happened... I don't know what to think. Smh. I don't feel right about it. Any suggestions? 😞