first off... the part about being a family and what we owe to ourselves and our children-- that just resonated so much with me. Also about my H not actually trying.
As you know, I'm in the "believe him" mode right now. This isn't on you. It is on him. You can't control whether or not he wants to try or not, how full-hearted his attempts are... you can only control you.
I don't know how to answer your question about what I'd do in your situation, but one option you might consider instead of full-on D, if you don't want to be the one to make that choice, is looking into what your state might have as options for legal S or a post-nup. That is what I've been thinking about, especially because I don't know that D is actually in my best interest financially. I know your situation is especially complicated because of the business, so if you aren't quite ready to pull that trigger but do want some security, a post-nup might be a good option.
Regardless of what you decide-- you have time. If he asks for an S, you are under no obligation to answer him right away. Say thanks, I'll need to think about this and end the conversation. Just because he is careening all over the place doesn't mean you need to go along for the ride. You take your own time to get to the mental place you need to get to decide what is best for you and your children. If that doesn't line up with his own timeline and he is insisting on this being a joint decision... too bad for him. He doesn't need your permission to leave. He can go. You will make your own decisions. And if it is to D and move on... you are fully empowered to do that if you believe it is the best for you and the children.
I've also had people on my thread remind me not to predict my own future. We don't know what will happen. People R after D all the time. And there is no way you can know right now how you'll feel if and the possibility arises. Or, you might be on a whole new path for yourself and an amazing new future that doesn't include him (except as the father of your kids... which of course complicates things.)
Also in/re the 4th of July plans etc-- if I were you, I would make plans on my own for what you want to do with the kids and he is welcome to come, or not. Drop plans for the romantic weekend. I think you ARE still DB-ing, you aren't in recon... this was something I struggled with a lot too when my H first broke it off with AP. It is so tempting to want to relax and feel like OK! We are in it now together! But these WHs are so, so confused.
Someone posted something on BlueSea's thread that I really liked, about being worried she's in a car heading 100 mph towards disaster. And the poster said, you know what to do... get out of the car. That doesn't necessarily mean S or D. But it does mean not letting his drama affect you.
Hang in there... you got this. Know that I'm doing this exact same thing right alongside you and thinking of you.
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing