I see how it is
I see how it is means you’re catching someone in their lies and you’re not going to let them get away with it. You know they’ve been messing with you and you’re ready to call them out.
You said you’d help me move, but now you’re at the bar with your friends.
You asked me for a favor, but now you’re telling everyone I owe you my life.
You said you liked me, but now you’re with my ex.