I have feelings for someone other than my girlfriend.
Okay, we've all been there. Why do you have feelings for someone else though?
I just like her more.
You shouldn't have crushes on others while being in a relationship. It's deceitful.
It doesn't count as cheating if we don't have sex.
Even if you aren't physically cheating, some people do believe in what's called "emotional cheating", if it feels wrong and you're withholding feelings from your girlfriend it could end up hurting her.  If you want to be with someone else, you should let your girlfriend know.