It's hard, isn't it?
For me, it's crucial not to get so overwhelmed by things I "have to" do that I freak out and wind up unable to do much. 15 minutes on Sunday afternoon making a day-by-day to-do list for the week helps me a lot, and checking off the things helps me to see what I DID do instead of what I didn't. When I don't have that, my best strategy is to think, on the way home from work, about what is the ONE most important thing to get done tonight, and put my focus there. Also helpful, when I feel crazy, is a "brain dump" where I just write down all the things. I feel calmer getting them down, and then I have the list to refer to if I decide to handle it that way.
How much can you delegate to your husband? Does he know how to cook? What things is he able to clean/maintain well? (It's my impression that most individuals have blind spots in home maintenance that make it very difficult for them to do a particular chore up to the other person's standard. Each of you should be doing the things you do effectively.) Does he feel that the kids keep him 100% busy, or is he able to get other things done with them/while they're around? I'm also working full-time outside the home while my partner is self-employed at home, and one of our biggest successes is agreeing that I plan the menu and he cooks all the weeknight dinners
. Also, every couple of years we make a date to drink an extra cup of coffee after dinner and sit down to make a list of everything that has to be done around the house, talk about how it's going, and rearrange who does what to cover the gaps.
When you were growing up, did you live with your father who worked full-time outside the home? That was my situation, so I consider my father a role model. I think back to what he did well or poorly, and sometimes I ask him how he handled things. Some of the main reasons I don't feel that he was "missing out" on my childhood are that he read our bedtime stories every night until we were teenagers, he attended nearly all of our recitals and parent-teacher conferences and such, and almost every weekend he would take us somewhere (like hiking) or do a project with us. Those things kept us connected. So those are things I do with my kids too. It's been a relief to me to hear that my dad often felt stressed, that he would find himself rushing to do yardwork or car repairs before it got dark while feeling guilty that he wasn't playing with us, that he often stayed up way too late in order to have any time at all for his hobbies and then struggled with insomnia on the nights he planned to get plenty of sleep--makes me feel normal!
For exercise, is it possible to work more walking into your commute and/or errands? That's my main exercise. Putting on some music and dancing and stretching with the kids is good, too!