Guys, put yourself in his shoes and explain to me why he's acting this way?

I don't know if he's happy with his new gf, but he's using you as a second string, basically. He likes you, but not as much as her. He probably does want to be friends with you, but you aren't a top priority. This is probably why he is being inconsistent. If he had been really head over heals crazy about you, he wouldn't have started dating some one else while he was supposed to be dating you. This doesn't mean he's a jerk, or that he doesn't like you, he probably likes you both, but right now, it sounds like she's more important. Sorry. I'm sure this isn't what you were hoping for,