My relationship is falling apart

I (M19) have an LDR going on with my girlfriend (F17) of almost 2 years. We've both exchanged our Instagram and Snapchat Id passwords, none of us really login very often. Today i came across a reel of some bodybuilder guy and saw my girlfriend's like there. I got a bit curious, for the first time I logged in her Instagram and randomly opened her chats with her female best friend and it was quite disturbing for me. I clearly stated to her many times that I don't like her looking at some other guy and the same applies to me. I made myself the person I wanted her to become. What I saw was that She was constantly commenting on thirst traps of random men on Instagram along with her friend. She even said "iske sath toh khulla khulla sex kar for lenge" for a guy(we both are virgin and are/were committed to losing it after marriage). The chats spanned in around 3-4 months. She's been doing this for a long time now. Let me know how should I approach her. I even stated her indirectly what I thought was a deep conversation and I thought she understood it very well, but then again I saw same thing going on. She was clearly making very lustful comments and simping on them and acting as if I don't exist at all. I was the guy she approached and I healed her so called past traumas and I thought that she was special. She even talks about marrying and despite of the different religions, I was ready to fight for her to be with her. I just feel so disrespected and so useless and as if I never meant anything to her. I'm thinking of discussing this later on with her as her boards are going on right now and I don't want to mess up with her exams. They're ending on 18th March TBH I'm devastated and wanting to end the rls as soon as possible. Please don't thrash me, tell me politely if I'm being insecure or is it my fragile male ego or something else