You are very smart to consider all of this. I am a SAHM (and have been for years), and ever since I can remember, this very issue has been in the back of my mind. I have a B.A. degree in Liberal Arts, but I never had a career (just a lot of low paying jobs), so financially, it didn't make sense for me to work.
A few years ago, my husband got laid off, and I was petrified. Thankfully, he found another job 2 months later. It really does suck to solely rely on my husband's income. I never wanted to stay home, but like I said, I had to since daycare would have cost more than my job (which is why I recently went back to school to get my phlebotomy certification).
Your situation, however, is different. You are currently employed, and I am guessing you have a high paying career job. If you become a SAHM and something happens, like your husband gets laid off or gets laid by that 23 year old slut Cindy (LOL!), you would easily be able to get another job, b/c you have a career to fall back on!
Women like me (who do not have a high paying job/career to fall back on) would be screwed. Since your education is behind you, go ahead at stay at home if you want. You can always go back to work. To be perfectly honest, I do not enjoy staying at home - unless you enjoy playing the game, "let's see how many loads of laundry and dishes I can do today."
Personally, I am incredibly jealous of all moms who work outside the home, b/c they are earning more income for the family, which means living a nicer life and taking nicer vacations (for me, it's all about nice vacations, b/c we all need a break)! Good luck!