Talk to her about it. Gather information by pretending it’s not bothering you, even though she’ll probably suss it out anyway. Don’t start making accusations, keep it civil while you talk it out.
The only reason to do this is to get attention, so you don’t need to question her intentions here. What you should be concerned about is whether she’s feeling insecure in the relationship or not, this would cause her to seek out alternative choices in case she has to break up with you.
If you start making accusations, then you’re driving towards a breakup. If you’ve been attacking her already, which is what your ‘exactly’ has me guessing, then it’s possible your relationship is already broken beyond repair and it’s time to start talking about breaking up.
You’ll find out how much she wants to preserve her relationship with you when you start talking about breaking up. If you can give her the attention she needs, maybe she won’t go seeking it out on social media. Your failure to do that is likely what drove her to do it in the first place.
Women need constant reminders of how wonderful and beautiful and amazing they are. If they’re not getting that from you, they’ll get it elsewhere.