Is my boyfriend cheating on me?

It sure sounds fishy to me. I don't know what legitimate reason he would have had for texting a girl, then covering it up. You could go on here, and try to trap him with other incidents, but what good would it do at this point? You know he's cheating with,or at best, lying to you, about this other girl. The problem here, is that your trust in him is destroyed, and he doesn't seem to want to do much to regain it. You may have to break-up with him and move on. I don't see how you can be happy with him the way things are now.

He knew what number he called that morning, of course the other denied it, it wasn't her that he called so she was telling the truth. If you could get his cell phone, you could text this girl, and set up a meeting for what you suspect he is doing, she will think it is him texting her, go wait for her, when she shows up for the meeting, you got him.

Did he say why he was calling this girl at 530 am? I think the best thing to do when you suspect someone is cheating is to take notice to things, such as, the call at 530. Don't say anything because if you do they will realize that they are being sloppy and not covering their tracks well. The call will put you on high alert so continue to take notice for a week or more. The only thing you can hope for is hard evidence. You may not find anything and may realize it's all in your head.

Trust is numero uno in a relationship. If you love someone you don't trust the hardest thing to do is let them go. In the end it is the better choice because you will live a lot healthier and happier life.

Calling a girl a 5. 30, that's odd. And as for calling on 3 way, he could have easily called her first to tell her what to say, even if he didn't she isn't going to admit it is she,
the reason he doesn't want to talk about it is because he is up to something or is about to with this girl, his reluctance to talk about it is a sure sign that he is lying to you, and making you feel guilty about questioning him is a sure sign of cheating, they turn it on you to take the focus away from what they have been up to and is 100% a sign of cheating.

Do you have that "gut feeling" that he's cheating? If you do, you're probably right. If he's not doing anything wrong, he shouldn't be avoiding your questions, etc. I think you probably know what's going on-why else would he be calling another girl at 5:30 am? If you want to check things out further, go through more than just one phone bill and go through his phone-looking for any recent texts or calls. I think CUDAGTO has a good idea but that takes a pretty ballsy person-go for it if your up to the challenge. Trust your instincts on this one, I think it's pretty clear but you might not want to jump to conclusions-depends on how long you've been with this guy, does he have a history of this, etc. Good luck.