Man that sucks. Yes sex if very necessary. Huge stress relived. I am sure the pressure of being a mom may have something to do with it. Scheduled sex is no fun. Been there. Have you looked into counseling? Not that you need it, but talking through the problem might help.
I have had my ups and downs over the years with my drive, primarily up. I would like to have sex at least once a day, if that doesn't happen, if the opportunity presents it's self, I will pleasure myself.
With that, I am also on "supplements" that totally increase my drive.
Hang in there. I hope things get better.
Happy early Fathers day.