Please give poor Julian a break. He does NOT like Alex. He likes YOU. Correction, he loves you. Just because he doesn't want to get married right now, or he doesn't want a baby right now, or wants to work on his script with Alex, it does not mean he is cheating on you.
Isn't it a little bit unfair that you get to work your little designer butt of in Tree Hill, yet he can't work on a script with Alex? You live in a small town in North Carolina. If he does not take this chance to work with Alex, he is basically unemployed.
He loved you enough to give up LA; give up a big movie; give up future opportunities that no doubt he would only get in LA/NY... so please, just drop it.
You are being way way way overdramatic and sabotaging your own relationship.
Oh yeah, and grab those birth control pills back out of the trash!
With much fondness for your cute clothes and raspy voice (but not so much your dramatics),