MPT is right. You do need a break. Go and do something nice for yourself. You will feel better and it will take your mind off things. This is just one of the down days. I too have several kinds of days like the following which I think you will understand too:
1. Very positive Days - I will change myself and hopefully things will improve. 2. Despair Days - I've tried everything and nothing works. I can't sleep, I cry myself to sleep. 3. I Give Up Days - I give up! I give up trying, I give up being nice. I give up feeling anything. 4. Cloud 9 Days - Needs no further explanation.
You're just having a I Give Up Day but you will feel better. And don't ever forget that your W is probably feeling very miserable right now too. As you've said, she hardly has time for herself, and when she does, she feels she has to spend it with the girls coz she feels guilty about not being with them more. She also probably feel she has to meet your needs but for some reason, stress, hormonal or whatever, the libido is not there and now more stress from argument over what was a nice weekend to begin with.
Please, please try not to have the sex argument. I think you have made it clear enough to her, an argument isn't going to help improve things. You will just bring up more and more unrelated issues in the argument which will just drive her further and further away, not closer.
Now, you go and do something nice for yourself and hopefully you will go back to having a postive day.