I understand exactly how you feel, really I do. There is absolutely nothing wrong with being direct; but give your wife a little credit for knowing if you are angry beyond your tone of voice. Body tension, facial expressions, etc., go into her being able to read you like a book. And even though you may not think you are being aggressive, the manner in which you say things could be killing any progress you hope to make.
For her part, I really don't think your wife has any clue how close you are to coming undone -- or she is choosing to ignore it. Be direct:
I am terribly unhappy in our relationship and I would like for us to work together in finding a way for us both to be as equally happy as can be. I do not feel I am being heard; if I am missing efforts to find a joint solution I need to know what I am missing so I can find a measure of hope. If finding middle ground is not possible for you, I would like to know. I don't want you to be anything you feel you cannot be; just as I can no longer be what I am not.
If this type of conversation puts your wife on the defense, you must keep your cool.
HER: "What are you saying? Are you saying if I don't have more sex with you, you are going to leave me? Is that what this is all about?"
YOU: "No. This is about us working together to make our marriage as happy for us both as we can be. I am not happy. I would like to be happy. We need to work together to get there. If we can't, then we can't, but I don't intend on being unhappy for the rest of my life."
Keep the conversation on the issue at hand. If she personalizes attacks, bring it back around to the issue at hand.
HER: "Well, you do this and you do that, and if it weren't for you doing this, then I wouldn't do that."
YOU: I hear you. But that is not the issue at hand. We can talk about that at another time. What I need you to know is: I am unhappy in our present relationship. I would like to be happy. We need to work together to get there. If we can't, then we can't, but I don't intend on being unhappy for the rest of my life. Can you work with me to make our marriage as happy for us both as we can be."
HER: "Why are you being like this? Why are you doing this to us. YOU were the one who did x, y, z, and I was the one at home doing q, r, s. Now you want a, b, c... blah, blah, blah. (Or insert any other attack you want)
YOU: "Okay, I must not being clear. Do you understand when I tell you that I am unhappy in our relationship?
HER: "You're treating me like a child. Why do you always treat me like a child?
YOU: "You are avoiding answering my question. It is a simple yes or no answer.
She will either answer you or she will continue to bait you and try to dodge the question. If she cannot give you straight answers to a very simple request, then you have some deicisions you need to make, later, after dinner. My point here is, keep the conversation on the point at hand and eventually she will have to answer you. When you get your answers to these questions, set another time/date to discuss what the potential solutions can be, and drop the subject. She'll need to space to breathe.
