Leave the child with someone, and focus on you first and the wife second. If you can get a good foundation under you, you can share what you know with her. I am making an assumption your motivation is greater than hers, if I am wrong she goes too.
If she goes, consider getting her some lessons separate from your own. Women learn differently than men. I think you will see a pattern, where something you are not so hot at, she is really good at it.
Having a toddler onboard while learning to sail, sounds like a big distraction. Hopefully you have family that can spell you, and can care for the child.
Then go sailing a lot, repeat, go sailing a lot. The more you go, the more comfortable it gets. Don't let the naysayers make it sound like rocket science, it is not.
PS: If you are talking about cruising, you will need to get moving to meet your goals.