I am not sure how much I can help you, but something I noticed with your question is that you seem to be overwhelmed and tired, and perhaps all of this, all the work you do outside the home, inside the home, and of course mothering, you may feel a bit stretched. You may need more time to yourself, to feel more "free" from stressors (even good stressors). Maybe you have a little anxiety going on as how to do all that you feel needs to be done. One person can only give so much. Then when you add on the guilt of your husband's irritation--well that can't put you much in the mood either.
Have you and the Dh had any date nights recently? Sometimes as a woman all you need is a nice sweet night of just hanging out, throw in some romantic overtures and no expectations of anything to follow but some cuddling. Men, well they love to start and end with sex...so of course the only way to solve this is real communication. Let your hubby know that you adore him and you love your intimate relationship--it's not him. Make an appointment with your OB/GYN and see if there isn't something physical going on they can help you with, and also work on your time and energy levels. You can't give the energy if you don't have it. You might need to do some shuffling to get the energy to do some things and get some things done. Maybe some of the things that you think are important to get done are not. And believe me, if you have little help, or not that right kind of help, it can make things a whole lot more difficult.
Take care, and good luck.