After a good time we started making out, behind his gf back. I always felt a but bad about her, because although she was a jerk and kind of a bitch ,no one deserves to be cheated on, so I ended it.
The last time that we make out I didn't really wanted to, I was already decided to end the things between us, but he was irritably insistent so I gave up and thought "just one more time and it's over...".
The day after all I could think about is how I was going to tell him that I didn't want to continue to be his "side chick" or "the other women" and if he wanted to be with me, he needed to break up with his girlfriend. Later that day, I sent him a message, he ignored me, a very childish attitude of him, but what could I say, he was a year younger than me, and in our age it makes a huge difference. He kept on seeing my Instagram histories, but not one single response. Two days had gone by. While hanging out with my friends, I received an "ok" from him of response to my text.
I could see what he was doing, he was trying to make me feel bad, guilty, sad etc about what happened, but I'm not that foolish, I grew up with a father that mentally abused me while growing up, so I just ignored it. 10 hours after the "ok", he sent me another message saying that he was "feeling" that I was mad at him and that he didn't wanted us to be in bad terms, which I responded that I didn't really cared and that was ok with the situation.
That was the last time that we ever spoke, he never broke up with girlfriend and their still together, their both idiots, because the two of them are unhappy with the relationship, but she is determined to make to be with him. Their good for each other, she's kind of a bitch, and he's a jerk that couldn't make a decision. Good luck to them.