You poor thing! You didn't even get the 40 year old when he was younger and still teachable! You might as well just give it up as far as working out any kind of deal with him that he'll pretend to honor.
I've been with my husband for 33 years now. He was 25 when I met him at 20. I lived under a delusion for 15 years about my prince until something happened. The clouds parted and sky opened up and I realized that our perfect communnication was non-existent and had been a figment of my imagination. We're still together, but it isn't a Venus/Mars thing. It's more this galaxy and another one.
50/50 is an unreasonable division of labor. Like marriage, it needs to be 100/100 on both sides especially if you decide to have additional children. The dynamics change with each new addition to the family.
We are the veterans of many skirmishes over the years and my husband who used to throw tantrums about going to the laundramat on Sunday afternoons because he wanted to watch his ball games 30 years ago still pitches fits about doing laundry today even though we have our own water and dryer and we have through the years had various technological wonders that allow you to pause, record, rewind, etc. his beloved ball games. True, I don't hear the old "I never get to watch a ball game and you know how much I love it" like I used to, but occasionally, he'll try to pull that out of his bag of tricks. We have had so many of the same arguments over the same things for so many years that I proposed years ago putting them down on paper and just referring to them by number when one of us wanted to run through that old tire script.
The truce that you make today probably won't work for you a few years down the road. When we had one child, she and I made special time on the weekend when his games were on by going out shopping and to have lunch at our little place. I found that removing myself from the house during his "special time" was the best solution and doing something that I wanted to do. When we had our second child, she was usually taking a nap, so I could leave her home with him or we could go out with her as well. In a few years, they'd be off down the road playing with friends all afternoon, so the dynamic changed again.
My husband is, always has been, and always will be a homebody. Now that he's in his late 50's I've learned that there's actually some pathology behind that. I thought he was just stubborn, selfish, self-centered, insensitive, etc., because he wouldn't plan or follow through on a date night. It turns out instead that he is mentally ill and that he has spent years and years hiding is fears of being outside his comfort zone by refusing to accommodate my wishes. He was actually diagnosed bipolar three years ago. It's like an illiterate trying to hide his inability to read or write. These days he just doesn't have it in him to keep up a front any more.
I know this response isn't what you wanted, but I hope you can see the humor and frustration and years of hard work that I'm trying to convey.
I had expectation and hopes and dreams, but so much of a family and long term relationships is just going with the flow. Over the years, I've learned that my husband and I have temperaments that are somewhere at opposite poles of the specrum, but we can have times when we can meet somewhere in the middle. To be successful over the long run, we've had to give each other space and alone time. I've tried talking and reasoning with him, but after all these yearz, I've finally learned that that strategy works for me, but he doesn't want to talk about anything or agree on anything or have to follow through with anything as a long range plan. I have known couples with more similar temperaments who have been successful at doing just that though.
Over the years, there will be times when your career or your family or your interests become more important in the family than his career, family, or interests, and that 50/50 split in repsonsibility isn't going to work at all. His career or your career will be soaring through the stratosphere while the other partner gets stuck with more of the household chores, which could be just what the domestic partner was wanting or it could be a major source of conflict between you.
As the kids get older, it's not the balance of work between you and your husband any more. It become all about the kids. There comes a time when you both realize(hopefully close to the same time) that there is no him and me or us anymore and that you both miss that. It's time again to bring things back into a better balance for everyone.
I think that the only realistic expectation to have is that things are going to change and that you all are going to have to change with them. There's no use trying to keep a scoreboard or tot sheet to make sure things are equal. They will hopefully be equal over the long run, but when one partner becomes seriously ill and the other has to cover the slack, the issue is not equality in the moment.
When one of you loses a job and the other has to pick up the slack, there will not be an equal division of 50/50 on income producing. That may continue for days, weeks, or years. I never thought when I became unemployed in 1993 (the first year of our marriage that my husband made more than 50% of the household income)that the situation was anything but temporary. Boy, were we mistaken! Man, did I see a side of my husband that I had no idea existed!
The easy measure of dollars in the paycheck or hours spent at the office worked for one of us then, but not for the one that had no paycheck and no office. In the Equal Rights movement for women in the 1970's and 1980's, this point also came to light in the debate over equality and equity. There are tangible measures and rewards like money and job title and material goods, and there are intangible measures and rewards like time spent with a sick child or a dying loved one or like the ability to create a home environment that is nurturing and loving and a sanctuary for everyone who occupies that space.
When my kids were growing up, they became involved in dance, so I became involved in dance. I think the same principle probably exists in team sports though. The group as a whole benefits by the ability of the individual members to excel individually. E pluribus unum. From many, one. It's a matter of balance. Allowing everyone to excel at being themselves so that the group (troupe or team or family) can become more than the sum of its parts.
Over my 33 years with "this man" and my almost 53 years on this earth, I have been beaten and battered and loved and nurtured into the person that I am. Hey, I started out a flexible and open-minded person! I should have had advanced standing in life because of that! Life may work that way for some people, but I suspect that more people just fake it for public consumption.
When everything is blissful, you want it to stay that way forever, but when life is in the crapper, you learn to embrace change even more as a survival mechanism. This, too, will change. There will be times when it doesn't matter how they change but just that they did change so that you had a different "reality" to deal with.
Expect change. Expect sacrifice. Expect selfishness. Expect good times. Expect rough patches in the road. Expect constant give and take. Expect martyrdom and heroics from both of you. Expect each of you to be committed to each other and to your family, and expect each of you all to be willing to do what must be done at any point in time for something bigger than yourself. Expect yourself to rise to any challenge and to make the compromises necessary to keep your soul in good health. Expect your partner to surprise you with hidden parts of himself that you have never suspected (the good bits and the not so good bits). Expect to see bits of yourself that make you proud, make you laugh, and make you embarassed. Expect life to work out for you and in spite of you and because of you.