I'm not going to crack out with insults on this one, but I seriously advise you to be careful. In my opinion, I think if a guy has time to think about his feelings for another girl when he's with you then it probably isn't meant to be. However, seeing him leave for another girl (especially your friend) can be heartbreaking. If it were me I would talk to him a little about it and ask how he really feels about you if he is already considering another girl. Worse case scenario? You break up. But it's not the end of the world. Sometimes God closes doors and you are left to go through others. It could be that you are meant to fall for another guy. Anyway, good luck girlie.
He's playing mind games. By telling you that he likes her "just a little bit," he's putting you on the defensive. He still likes you more than her, so if you just keep trying harder, and doing things for him, and trying to act and be the way he wants you to, then he'll keep liking you more. It gives him all the power in the relationship, and turns you into a doormat. I would advise you to run, but if for some reason you want to stay, then you've got to take some of that power back. Your attitude has to be, "yeah, you only like her a little bit because I'm so freaking awesome." Cheesy, I know, but you need to approach him with that attitude. Best of luck!
He is not a man at all, if he was a real man he wouldn't even look at another woman or think about another woman but u and id becareful about ur friend too because if she doesn't discourage his feelings towards her than u can't fully trust her either. Guard ur heart plz