Putting away the knives, implicitly declaring a "ceasefire" and trying to act like adults is the first few steps
Yes, courtesy, please, thank you, no name calling, trying to use language like an adult, DESPITE how you may FEEL.
A person can be furuious but still offer up a please and thank you... and over time it DOES sneak into the brain and warm the relationship...
I am onside with pupper here, end the divorce proceedings, act civil, etc... That's best after an affair has just ended or is fizzling out due to final showdown etc... Being wreckless and demanding apologies at this stage will just invite the war to start all over again...