You are correct in your first point about a homemaker's job being harder than her working husband's. No question taking care of kids all day is a b*tch. Most men would be begging to go back to their jobs after a week of wiping noses, fixing lunches, running the family taxi, etc. It's hard work and I know from experience having raised four kids and doing plenty of the above.
My ex-wife was a stay-at-home mom for 15 years and I'm convinced it's what led her to go "batsh*t crazy" in her late 30s as another female poster state above. This happened even though she had weekly nights off where she went shopping, etc., and I took care of everything at home. We also had date nights just about every week and took a week-long vacation at least once a year, just the two of us. I also bathed and put the kids to bed every night and did plenty of other stuff to try to help. Not saying I was a hero or did anything extraordinary, just stating facts.
However, your point of women not tending to cheat as often as men is incorrect. The perception is that men are lust-crazed goons that can't help but look for strange and that women are more self-controlled and simply file for divorce when they've had a belly full. But the facts are at odds with this narrative.
"...the incidence of women straying has accelerated in the last decade. The Archives of Sexual Behavior reports that researchers at the Kinsey Institute found that women are now committing adultery at the same rate as men."
http://www.psychologytoday.com/blog/repairing-relationships/201210/why-do-women-cheatAnd here's another...
"Although the most recent high-profile infidelity scandals all involved cheating men, a new study finds that women cheat at about the same rate as men, though often for different reasons."
http://abcnews.go.com/Health/women-cheating-men-study/story?id=13885519#.UX6Ex8qg30o