I can't comment too much about ways to make a marriage work (I divorced my XH!!), but from seeing friends and family members who are in successful marriages/partnerships, have kids and both work FT, there seems to be a trend...
-good communication.
-sharing of the responsibilities equally (parenting, mental load, house stuff etc). That could include outsourcing things, so some have a cleaner come in weekly.
-they also seem to try and make sure that they make time for each other to do date nights (either at home or actually going out) or things together, and give each other the time to do their own thing (meeting friends, hobbies etc).
^the sort of things I wished that my ex would do with me!!
My DB and SIL both work FT (in "big jobs"), but they've compressed their hours in to four day weeks (I know not probably possible with teaching!). They take on equal responsibilities around the house and with their kids. SIL gets time to do her hobbies/see her friends, and vice versa. They've got a cleaner coming once a week to sort housework. The way they do things really works well for them.
You've got an insanely hard job (I'm a nurse working FT but I wouldn't be able to do your job so you have my deepest respect), and I promise you that you do so much more than you realise. Please don't feel like you don't bring anything to the world. Your DC are young and from experience, parenting young kids is bloody brutal and like you're on a treadmill the whole time!! Things do get better as they get older (new set of things to worry about but that's another story).
Is there a chance that you can get in a cleaner once a week, or once a fortnight? At least then that's the housework taken care off. I know everyone says it, but batch cooking or the Gousto/Hello Fresh boxes might help with sorting meals. I batch cook every so often and get my groceries delivered (saves me a lot of bother). I've got a robovac that does the floors for me each night, so at least they don't look too hideous. And my DC are a bit older now (10 and 16) so I draft them in to give me hand around the house. What would make things easier for you guys as a family?
Are you getting enough sleep? I imagine that after you finish at work, you have all the usual routines of sorting kids, supper etc, and then marking, lesson prepping etc. It must be non stop. I hope you managed to get a good sleep last night. Really hope that you and your DH can have a talk about how to sort things moving forward. x