You know - do not underestimate the effect on the kids - or the effect YOUR responses can have.
The more the kids see YOUR pain, the more scary and unsteady their world seems.
The more you keep life on an even, "normal" keel, and plan and do fun things with them, and help them to see that their dad is "sick" or weak in some way, not evil - the better for them. Model healthy boundaries and healthy recovery for them.
My S21 was 15 when I learned about my H's affair. This was brief, H never left the house, well-reconciled within a few months. I thought S21 was the least affected by it - but he still feels resentment over it.
