Alex, I am sorry. My son's -mostly-, reaction was the only reason I told myself I would kill H one day. This feeling of seeing your kids like that and trying to be "good" to their mother and validating and at the same time hurting inside yourself is a painful-painful experience.
If you feel your wife is not letting the kids express themselves, tell her. Take her aside,in privacy and tell her she is responsible for how the kids will deal with this and you that you wont take her bailing out, looking after her own a$$ while the kids are falling apart. What is going on between you is another story adn SHE is NOT the focus. And Alex, be honest with your kids and show your feelings also. My experience was that that made them feel they could express their feelings as well. At least to me.