nobody telling Dale about his cheating wife would never fly in real life (King of the Hill)
someone would eventually accidentally tell him or she would have gotten caught and I'm sure Dale's crazy ass would catch a charge for shooting a Native American
I read a theory randomly that Dale always knew that Nancy was cheating on him but decided to play ignorant of the infidelity due to the fact that:
1. Despite Joseph not being his Dale grew to love Joseph as his own son and didn't want to break up the family creating a broken home for him.
2. Dale knows he can get away with all of his batshyt crazy activities (owning tons of guns, tunnels and surveliance cameras everywhere, paranoid of everything, scamming the government, etc) without Nancy stopping him because she won't risk exposing herself by doing so... so she's a ride or die by default.
3. Dale still has Nancy by his side so he can stunt on Hank of having a better looking wife than he does and lowkey taunts Bill that he actually has a loving wife unlike him.
4. Despite everything Dale really just didn't want to give up his pawg wife...