I'm going to break up with my asexual girlfriend
What is the reason you have decided this? Why would you want to break up with her?
Cause I need to have sex sometimes.
I understand. If you don't feel like you have much in common with your partner it's good to break up with them. Better than letting it drag on forever.
I like having sex but I don't want to have sex with her. She doesn't have a sex drive and that makes me frustrated, so I need to find someone else.
I understand what you are saying and I think you are doing the right thing. You need to know what will make you happy in the long run in life.