I'm 17 years old. I come to this subreddit because this is the only place where I feel I can expose my true feelings for what has recently happened.

I've been dating this girl for 3 years. Last February, she has ramped up the affection and love which I find to be a red flag. I didn't do or say anything about it.

Late February, she claims to start feeling like shit and becomes "depressed." She becomes unresponsive, so everytime I start to go cold on her, she begs for me to understand what shes going through. I continue to comfort her as best I can because I didn't know any better.

A week later, I check her DM's. She's been talking to another guy from a different school since the beginning of February. There are only three moments of flirty texts, but she insists that they will never be together (shit testing the guy). I break it off with her the same night, and told her I can't trust her and I feel like you take me for granted. She said ok, and gave me my sweater back.

A week later, she says she still has feelings for me, and wants me to understand that she's going through "depression." I play hard to get and refuse, but I eventually ask her on a date. We get back together. I had the best sex of my life, we go play soccer, we celebrate my birthday she's being overly flirty with me, and being really kino. Today, she changed, and reverted back to not putting in too much effort.

I check her DM's and what do you know, she's been sending memes to this guy not stop. Not even flirting and only responding when he texts.

I text her, "You should really change your Instagram password." She left me on read. I tell her friend about it because she gets upset when my "girlfriend" treats me like shit.

I don't know guys. I need a reality check and I really want some insight on to what just happened. My emotions are clouding me right now and I can't seem to get straight.

What do I do next? What should I have done? How do I get better? How do I game other women?