Why does my friend keep liking all of my ex boyfriend’s pictures? Should I unfriend her?

It is none of your business. After all, you exed him. Butt out.

TALK to her before you act out. Do some inflecting, and find out why it bothers you. I would not like my friend doing that either, because it would make me question if she ever heard anything I said about the guy, and make me wonder how long she had been scoping him out. If she gets defensive, or doesn't really care how you feel, then by all means tell her what she should go do to herself. A true friend does not do things that they know make their friends uncomfortable.