eclipse-
Parents fighting is the toughest thing in the world for kids to witness.
This is even true for older kids, much more so for younger ones.
If you don’t allow your kids to go, they may feel that they had to choose between their Abba/Tatty and Ima/Mommy, and feel very guilty for having hurt their father.
As painful as it will be for you (and I am not minimizing your tzar at all), your kids will probably be much better off if they know they can do something good for and show love to one parent without betraying the other parent.