Don’t know to comment on your situation inasmuch as how you must be feeling etc but I wouldn’t stay together for the kids’ sakes.
My folks broke up when I was pretty young, my mum, little bro and i moved back to a village in scotland (from kent) and she brought us up with help of her sis and mum. I only saw my dad once a month and i guess i did resent my mum for a long time but as you get older you realise how tough it must have been for her and you respect that decision. I also believe for her to stay in that relationship would have been detrimental, hard as it was breaking up was the best thing for them to do. For me as much as them.
Horses for courses but I wouldn’t stay together for the kids, as said they prob know/will find out in due course.