I have a different perspective. There are many similarities here to my marriage. Really, I feel your pain.
From my experience, I would say that it's not that he's immature, irresponsible, or being passive-aggressive. He just has different goals and values than you have. And, I would guess, a different personality.
My husband and I are also similar in logical/creative, but I am much more practical and he is a dreamer. He's now in his early 50s and has never had a job for more than about 5 years. He has started numerous freelance businesses, none of which have ever made more than $20-30k. He actually has programming skills and has in that time had well-paid jobs here and there, but he HATES it. He's just too much of a free spirit. He too has quit jobs spontaneously (when we had a newborn) and started businesses without thinking them through.
To make a long story short (I could go on for hours, and have), I have over the years alternated between being very resentful and realizing that this is just WHO HE IS. He was already in his mid-30s when I met him and he was still living with 3 housemates, eating canned food (doesn't cook), and loving spending hours writing philosophy in coffee shops. I knew this about him when I married him. I had no idea how it would play out as we got older, bought a house, had kids, but even so, it's what I signed up for.
We've been together 20 years, and though I can certainly come up with things to complain about him, I still love him dearly. He's an amazing father and he reminds me to focus on the joys in life, not just the practical side.
Wanting to do work you love could be naive, but it's not a bad goal. FI isn't the only reasonable goal (though it's mine too). It's not like he wants to sit on the couch and drink cheap beer and watch soaps all day.
What I've had to do is realize that my needs/goals are not better or more important than his needs/goals. I have had to remember that his behavior is not about enjoying the fruits of my labor out of laziness--he's just working toward different goals and has different needs. I need the security of saving for the future; he doesn't. Would he like it? Sure, but he doesn't need it. He needs to have opportunities for self-expression. Would I like that? Sure, but it's not a need. (fwiw, I don't quite get it either. But it's not wrong or irresponsible).
Have you told him you want him to spend less or earn more? I assume if you were FI all this wouldn't be an issue. What saving level do you have to be at to get there?
Do you tell him you feel resentful? Have you brought up the day care/SAH issue over and over again? Can you try to find a win-win solution? For example, would it work if he were willing to be a SAHD 3 days a week, get a babysitter for 2 days a week for him to do only the projects he loves, and only if he makes sure they cover the daycare cost. I think if you went into it as "How can we meet everyone's needs," you'll both be happier.
Are there changes you can also both make that will help you meet your needs? Would a play money budget or a certain savings rate make you feel like you're making enough progress? Could you do something radical like move to a lower cost of living area to reach FI faster so you could be the SAHM?
I think you can bring up all these things as "how can we make a our lives work with a baby" and not "you are a mooch." :)