Do you honestly start bitching about the lack of sex if you haven't had it in over a week? Truthfully? If so, that right there is enough to pressure a man and drive him right in the other direction.
Not all men thrive on having a woman who is hot to trot all the time, much less demanding of sex. True that may be some men's dream...but not all. I'm married to someone who shuts down if I put pressure on like you do. If you two are having sex at least three times a month, then I'm fairly certain yours doesn't have the issues mine does....but back off woman! I guess from my impression of your posts...you aren't giving him any time to come to you REALLY on his own accord without expectations from you. Have you even considered what your absolute minimal time for frequency as far as sex is concerned would be...and try to compromise on that with your H? Or are you going for YOUR number in frequency that you would prefer? Honest question, I don't know. If you are going for your preference of (oh lets pull something out the air)...3 times a week, then he's not going to meet that most likely. So you ask him what his preference would be....lets say his is the three times a month (once again pulling out of the air)...due to schedules or whatever. So shoot for something somewhere in the middle...like once a during the week sometime, and once on the weekend maybe.
Can you give us an idea of what life is like in your household after a week of no sex. An example of a conversation if you don't mind...that could be helpful.
I have to agree with Corri though, I sense a definite lack of empathy from you. Are you even trying to understand why your H is behaving this way...or are you just trying to find the magic combination to change his behavior?
Oh and reason's why not to have an affair. YOU ARE MARRIED. YOU TOOK VOWS. You aren't having sex once a month, once a quarter, or once a year. While you may not have the frequency you would prefer....if that is the ONLY issue in your marriage, you have it good sweetie. Don't go looking for some on the side and risk your marriage, that's a stupid gamble....when chances are there are other issues preventing you from obtaining what you want. Having an affair will only make the situation WORSE.