I have heard your guy's alibili for why he doesn't have sex with you night after night: he's too tired. If he really wanted to have sex with you, he would find a way to accomodate your needs by approaching you during the daytime or on non-work days. But, he isn't making the effort. What's more, he taunts you by seducing you with promises and then pulls the rug out from under you. It sounds like your boyfriend has a passive-aggressive personality disorder.
Passive-aggressives don't directly communicate their anger; instead they indirectly convey their anger through witholding actions, in this case by not giving you sex. Even though he isn't slamming you directly, his refusal to have sex gets the 'screw you' message across all the same. The more upset you become, the more he figuratively gets his rocks off. What you need to realize about a passive-aggressive is that this way of handling anger is built in to his personality. He knows no other way of handling anger, which means that he will need a good therapist to help him learn how to be more direct when he is angry.
Realize also that there are all kinds of reasons why he wouldn't want to change his ways. For one thing, he probably grew up with an abusive parent, which means that he learned that it is 'safer' to release anger indirectly rather than confront his parent directly. He has carried this pattern into adulthood. An entrenched pattern that originates in childhood isn't easy to break. Old habits die hard. It is said that no pattern continues unless the person experiences pleasure by holding on to the pattern.
What is the pleasure that he obtains by being witholding? For one thing, he gets to continue a familiar pattern. It is comfortable to stick with what we know, so this explains the most obvious form of gratification he obtains by witholding. What other gratification does he get by witholding sex? Each time he witholds sex, he releases his anger indirectly, which gives him a secret rush. He would have to give up the gratification he gets from dumping his anger and trade it for a more mature approach (talking, discussing, and resolving the angry feelings), which is far less gratifying than dumping on someone.
What can you do to impact on this situation? No pattern changes unless it becomes painful to continue. He needs to associate his pattern of witholding when he's angry with pain. How can we make it painful for him to keep up this game? First, you must remove the gratification he gets from witholding sex from you; and second, if possible, he needs to experience pain and discomfort as a result of his witholding behavior. If it hurts him to continue what he's doing, then he will be motivated to get help to change himself. Because this guy acts out his feelings instead of talks, talking with him about what he is doing will get you nowhere.
You are going to need to change your behavior in order to reach him. Here's how: The next time he promises you sex later that evening, smile (so that he sees he isn't getting to you any more, thereby removing his secret pleasure) and tell him that you won't be holding your breath for sex. Now, here's where you can make him feel the pain. Tell him that because you know he will be asleep, you made plans to go out. If you make yourself less available to him; if he begins to feel frustrated by the loss of your company, he will experience the discomfort that we want.
This change on your part is going to throw him for a loop. I wouldn't be surprised if he actually jumps your bones. Keep in mind that even if he does come after you sexually, that his improvement will only be temporary. As soon as he becomes angry again, the witholding behavior will resume, unless he gets help. You may need to go through a couple of the above cycles before he starts to wake up and realize that you are distancing from him. If he asks you why, then you could point out to him what his problem is: that when he's mad, he witholds, which is a relationship busting behavior. Then, you might add that if he ever hopes to succeed in having a thriving relationship with you or anyone else, he is going to need to learn a healthier way of handling his anger. If he isn't willing to own up to his 'stuff, ' then you will have to decide if you want to stay with someone who tortures you and shows no hope of change. I hope, for your sake, that he is the type of man who is willing to look at himself and get help.