All I can advise on is to talk to different girls, get to know them. Find out what you like about them and what you don't like about them. You may eventually shift your feelings.
You can also try talking to the girl more though. But if you plan to persue a relationship with her, you must be dedicated. Long distance relationships are extremely hard to keep up with. Everything is pushed moreso to the limit than in a normal one. Especially if you can't regularly visit.
He's both right and wrong. She can cheat on you alot easier, and so can you. Whether she will is up to her. Trust is a major issue with long distance. If you can't fully trust her, don't bother.