I want my girlfriend to get an abortion?

My girlfriend is pregnant and i am not happy about it. I was going to break up with her when she told me she was pregnant. I haven't been happy with her for awhile with her. Plus i have decided to start a relationship with my best friend Leslie who just moved back to town after being gone for 5 years. We just realized how much we love one another. I think it's best if she has an abortion I'm not ready to be a father especially with her. I want to move on and start anew with Leslie. I haven't told her yet because i don't want to hurt her. What should i do?