If me and my girlfriend were on a break and i hooked up with another girl am i a cheater?

So my gf of 5 months and i broke up about a week and a half ago. The relationship was never easy. We always had issues from the get go. I love her but things were just not going good. We broke up and had been hanging out and doing all the things we normally did while we were together (kiss, have sex etc.). I've asked her multiple times to be my girlfriend again but she continued to decline and said she needed time. Today, i hung out with a girl i had met recently and she kissed me and i kissed back. Told my ex gf and she stormed off calling me a cheater. I am extremely against cheating and morally would never do it. I feel as though since we weren't technically together, it wasn't cheating. She wouldn't commit to me and had me waiting on her... Thats not fair to me.