Was this right of me?

Had a girlfriend of over a year. Found out she lied to me about being a virgin at the start of the relationship (I only found out at the end) and that she had cheated on me. I dumped her, instantly started talking to this other girl that was in my class at college. Things progressed, ended up meeting a lot over the summer. I was still texting my ex through this though. I really liked this girl and she really liked me, we ended up having sex when Iwent to University (she was a virgin). I visited home one weekend, met up with my ex. The girl that I was seeing found out (didn't tell her) even though I was texting this girl the very same week. She completely stopped talking to me and now I'm back with my ex.

The girl I was seeing didn't take it very well but I've made no effort to talk to her about it. Just went straight back to my ex. Was this right of me? Or am I a complete tool?

You're a tool, but I'd argue different reasons to TheAJK. The fact that you went back to your cheating ex isn't the problem, it's that you kept texting her whilst with this other girl and then met up with your ex whilst still with the other girl. You should have broke all contact with your ex when you split for a start, you definitely should have done it before getting close to this other girl, definitely definitely before sleeping with the other girl and if you were going to meet up with your ex you shoud have at least had the decency to tell the other girl it's over first.

Basically the entire thing shows you didn't actually have feelings for the other girl at all, in which case you shouldn't have led her on with all this.