I need your help! Wives of business owners

I’m a SAHM at the moment and my husband is an electrician. We have 2 boys that are 2 yrs old and 3 months old. My husband has a good steady job ( paid sick days and 4 weeks vacations a year) and makes enough money to comfortably support our family. I’m currently on paid maternity leave but I don’t have a job to return to because we had decided to shortly try and have a third child so i would be home with the kids and it didn’t make sense to return to work at the moment. He opened ,a while ago, his own construction company with his friend and he was working side jobs to try and start his company and eventually when business was steady he would quit his job and work as self employed. I’m super happy and supportive of his dream but now he’s telling me he’s planning to leave his job by the end of this year and thats when all hell broke loose. Going on his own means no steady pay check and no insurance for our family and with 2 little kids it scares the hell out of me. I know that starting a business means a lot of financial sacrifice and while I want to be a good supportive wife I also don’t want to end up in debts just because he can’t wait. I’ve tried explaining him that I don’t think right now is the right time to quit his job because I don’t have one to return to. Also this changes everything because I would need to find daycare service for the kids and I didn’t put them on a waiting list so it will take a lot longer to find. (here in Canada people sign up their kids when they’re preggo that’s how full daycares are) And my youngest is 3 months old and I don’t want him in daycare 😞 we have been fighting for the past few days and I can really use some advices from other mamas who have been thru this. Thanks in advance!