Take charge of your finances. Downgrade vehicles if you've got new shit. Exercise thrift and self denial on some things. Have her sit down with you over the monthly bills so she sees the way money goes through the house. Tell her you need her help to get ahead so that you BOTH have an easy retirement, as well as yearly vacations and god help you a date night every week or three away from the kids.
Straight up troof dat.
I am working that right now. Just downgraded TunerWife from a Ford F150 Crew Cab, to a 90 Wagovan. I downgraded myself from an 03 Element, to a CRX (which is actually an upgrade). Liability insurance on both, storage insurance on the others. We went from about 28MPG combined, up to 50MPG combined. Saving ourselves about 400 month in fuel alone.
If she is staying at home, have her sit somebody elses kid along with yours. Daycare is expensive, she can find someone to watch. No more than one tho, or at least no more than you can deal with having in your home. Also, put her to work clipping coupons, and shopping/cooking frugally. That means fewer boxed and frozen foods. No microwavable shit, the cost per meal is crazy. Also, no garbage snacks for the kids. If there is fruit and veggies in the house, and not garbage, they magically eat the fruit and veggies. With the right coupon action and timing, she can cut your grocery bills by 60%. Not joking. Check out "Coupon Sense", it just takes time, which she has plenty of if she is staying home. Have her start winterproofing the home, sealing up windows and doors. More blankets, less furnace.
Being a good wife and homemaker is a full time gig, and can make a home run very cheaply and smoothly. You just got to get her motivated.
If you make her work, and bring on a bunch of other headaches in the process, you are not going to be any happier.