Most Helpful Girl
Pick one. A guy constantly hanging around his ex is SO fishy and the new girl won't stand for it much longer.
Most Helpful Guy
NO, you should certainly not be hanging around your ex with a new girl. It's disrespectful to both of them. But, don't worry, keep bringing the new girl around the ex, and the problem will solve itself. It'll just be you and the ex soon enough.
Realistically, if you can't focus your attention solely on the new girl, you're not ready to move on. There's nothing wrong or unusual about being single for awhile after a breakup.