Okay... take a deep breath. It's not that bad. First, keep in mind that your son needs to "deschool" and kind of get out of the mindset of "school" so that he can start looking at learning as a completely different process, and help him start to figure out what he wants to learn about and you to see how he approaches learning things. This can take some time. You might want to search this forum for "deschool".
But where planning is concerned, take it one week at a time. Don't try to plan too far out, but yeah--a plan might make you and your husband feel better. Look at your week ahead. Look at what opportunities you have, what your son is "into" that week and what you'd like to do for that. See what homeschooler activities are going on. Plot them down in your book for the week. While "deschooling", this might be it, really. You might want to just figure out if you want to take a field trip or go to a homeschool outing that week.
Once you're starting to plan, you can do the above and then look at the materials you have and fill in the activities from each that you want done. Make sure to plan for about 1/3 of what you actually want to do at first. You'd be surprised where things lead and how you feel and how long things can take--especially when, in time, your son wants to expand on things.
By doing a plan one week at a time, you have some kind of plan/structure for yourselves; but you have the ability to change them each week as you discover what you like, what you don't like, what your son responds to, what he's interested in, what opportunities arise as you find more out about what's available, etc. When I taught in public school, I learned quick not to try to plot my whole year out. Stuff happened. You had to be able to adapt on the fly. This is all the more true in the homeschool environment--where opportunities to deviate and do what inspires you are way more common.
I would try to make a deal with your husband, though, to give you an hour or so each Sunday night for "lesson planning". This not only gives you a chance to sit down and really think about it, but might also help him feel like it's being given the attention he worries it won't have.
Hope this helps!