If your guy is always late, it doesn’t mean he’s a cheater. It does mean he doesn’t respect your time as much as he does his own.
I’d ask yourself if his chronic lateness affects his own life — or just yours. In other words, is he so late to work and meetings that he can’t hold down a job? If his being late affects his own life to the extent that he’s having trouble functioning, then he has a serious problem.
But if he’s only late for you, there is something [i]you[/i] can do about it. Obviously you’ve told him how much his being late bothers you and it doesn’t help. So instead of trying to change him, change yourself. If he says he’s going to call at 10 and he doesn’t call at 12, don’t be available. It’s that simple.
You decide what an acceptable margin of lateness is, and stick to that margin of lateness out of self respect. For instance, if you think that fifteen minutes late is acceptable, then when he says he’s going to call at 10, you can allow yourself to be available for him until 10:15, and after that, turn off the phone. Or, when he does call two hours later, tell him that you’re sorry, but you were expecting his call at ten, and now you’re busy. Sorry! Then hang up.
If he cares about you enough then he’ll honor your time and the commitments he makes to you about when he’s going to call. If he doesn’t, well, then, find someone who does!
But it sounds like there may be something deeper going on and complaining about his being late is your way of admitting there’s something wrong, but avoiding the real subject. You mention he’s changing a lot, that you’re long-distance now with him, and that he’s not on line or on the phone when he says he will be. I’m wondering if what’s really happening is that you think he’s changing his life and he’s not interested in having you in it any more. I guess that’s where your fear of his cheating on you is coming from. So if you put aside his being late, and look at the other changes — you’re both long-distance now, and he’s not showing up for your long-distance “phone and internet dates”, he may be more interested in someone who’s there in the present rather than on the phone or internet, and hasn’t told you so directly.