This guy must be something pretty special if he's still your boyfriend after the whole texting-while-sexing incident, but that's just my two cents. Let's see what the cards have to say about your mystery man.
Men are relatively simple creatures compared to us deeply complicated women. Yes, his attention has strayed and it's leaving you off-kilter, but it won't help matters any if you try to fight fire with fire. Consider the scenario: He's got a new job, that's totally awesome! Have you showered him with genuine appreciation and respect for the achievement, or are you continuing to nag him about bills that have been neglected during the lull in paychecks? Maybe there is some little filly at work that's making him feel like a stud, that flame will cool once your man has settled into a daily routine at the office. It will cool faster if you keep the home fires burning with intense passion. Next time he whips out his cell phone during sex, ask him if he wants to take some saucy pictures of you in your new lingerie. Don't get caught up in drama and stress, that shit is poison! Instead, get to work on reminding your man that you don't care where he goes to work up an appetite so long as he comes home to enjoy dinner.
So there you have it: Everything will be okay. Start respecting your man and he will stop exhibiting behaviors that make you feel unloved. You have your work cut out for you!