M.J.
I write about job-hunting for a living, so I have a few ideas:
1. Highlight anything you've done as a SAHM that remotely connects to the business world. For instance, have you done any volunteering at schools, church, charities? Anything there is experience (even just the fact that you worked with diverse personalities is beneficial), so mention it on the resume.
2. Have you stayed involved in any professional groups or taken any classes? Again, those are worth mentioning.
3. Have you considered temporary work? This can be a super way to update your experience and get your foot in the door at potential employers. Many temporary-to-hire positions are out there, too.
Good luck!