I am a business owner, I will not tell you what type of business because the Borg could track me if I posted my business. My biggest advice do not listen to the naysayers. The naysayers cannot stand someone getting ahead in life, they will be negative, do not let them get to you!!!. I worked at my old Job for two years during started up. My wife ran the business and I helped her after work and on the weekends. Now I run the business.
Service businesses are the best and most profitable. For example house cleaning, cleaning after fire and crime scenes. You can make over $100,00 an hour doing this and there is lots of work. Clean up repo property's, not only can you make over $100.00 per hour you get to keep what is on the property, sometimes this can be worth more than the $ per hour. Window cleaning; small start up big profits. Lawn Care; medium start up huge profits. You get the idea, if you start a service business you will make it, but you will work your ass off. You will get rich if you manage the business properly.
My biggest advice don't both of you quit your jobs. One of you start up the business and the other help out. There is huge advantages for the woman to own the business, get your Dunn's number, Federal Idea number, County and State registration all under the wifes name. This allows you to get loans and government jobs.
Work hard I do not understand why, with all the money out there for the taking anyone works for someone else making them rich.