I recently found out sth that really bothers me guys and i need your help.

My LTR sent me a screenshot of her fb messages to show me that an ex of hers sent her a kiss( he's a real beta so until now no problem).

In the "active now" list i was me, her best girlfriend and her sister and then an unknown guy. Because i know that in that list appear firstly the people you text or visit their profile the most, it gave me some doubts so i asked her (yeah i know it sounds insecure etc) if that unknown guy sent her a text until now and she said that no, he appears on that list because they recently became friends on facebook(to tell me later that it happened 2-3 weeks ago "what do you thought when i said recent, 2-3 days?").

I give a look on the guy's profile and i notice he was the popular type in highscool. And that's where the PROBLEM comes: i saw she liked a couple of his photos, unactualised photos from the past who nobody likes anymore and receives no notifications from, which to me it seems from her action sth like "hey i'm here, notice me". I ask her about this and kept telling me "a like means nothing/ i did it when we were fighting and weren't talking".

Guys, don't misunderstand me, i don't have a problem with my gf liking pictures of other men, what really bothers me is that she didn't even know that guy and gave him likes at old photos, to notice her i think, it's the only explanation i have.

I'm thinking to break up with her, she lost my trust, even it could be seen exagerate in the eyes of others.

Guys, i want you to give me advices about what should i do now with her, even if you probably see my problem weird and you think to judge me, it really bothers me and i need helpful answers.

Sorry for the mistakes, i'm not a native.