I'm D so my opinion is a bit skewed.

After our 2nd child was born, my exW's (36 at the time) libido evaporated. She was also a stay at home mom. Constantly tired, constantly thinking about the kids. She told me that after being touched by the kids all day that she just did not look forward to being touched by me.

What really helped us was establishing a solid schedule for the kids - fed, bathed and in bed by 8:00 every night. The only time we had for each other was after the kids went to bed and we had cleaned up. It was also critical that we both go to bed at the same time and early. We also made an agreement to not let the kids sleep in bed with us, and to allow for the closing of doors. I also made sure that we talked about sex more often.

My younger brother now has exactly the same problem, and the same symptons that we had. After his W goes to bed he stays up late watching TV or working on the computer. Several hours after his W has been asleep he goes in and expects his W to be hot and ready for him. Very frustrating for him, but understable.

The real tragedy here is that women in their late 30's and early 40's are just reaching their sexual peak. All while they are in their child rearing years.