From your own description, you blaming instagram, social media, instead of the obvious is really interesting.
Sometimes they end up with someone who never understood them and still wants them to be something else.
OP is probably #2.
Once you get the ear worm that the grass is always greener you don't appreciate what you have in front of you. I'm not necessarily saying you're wrong but we did start out with significantly more compatibility than I think you're implying. It was only when comparison became the norm that we grew more distant. She wants the ability to brag to her friends and the internet.
Maybe she was always this way. Maybe she wasn't. It certainly was not obvious to me. People change and perhaps I have too. Some of it I think is escapism from the banality of life.
It is the difference between social compatibility and value compatibility, I think. If you were in the same cultural group and didn’t communicate values, then you were compatible at the moment. When social media came along if you both shared your value perspective you both might have responded as you did (or, if you shared her perspective, as she did). Instead it split your sociocultural compatibility along a value axis.
The best way I’ve found to communicate this in a straightforward way is as being seen/understood, which is when your partner understands and appreciates who you are and why you’ve done something, most importantly when you don’t want to do something.
edit to say: I made it sound like it’s too late, but I didn’t mean to. For social people, social media is more necessary and they can be more effective in it. It sounds like your partner is more social than you. They probably value the network more than they resent it because of this, and are probably feeling the reduction in offline opportunities for socializing. If so, this is likely functioning at an evolutionary level for them. If you found a way where you could see some positive aspect of their network and engage with that, it might alleviate their attempts to get you to engage with the materialistic aspects.
It also might not, but something like this is probably worth a try.
The fact that they dissociate and excuse their partner’s abusive mentality is whats interesting to me. And given the post voting, it seems like a lot of HN is quick to do so too.