I agree whole heartedly, you ARE showing your kids what a good parent is. When in IC with the first M, I was told to just take care of my R with the kids and not feel it was my job to manage the R between the kids and their F. I was told to let it take its course, not to intervene, and not to apologize. Let him have his R with them and let them find out who is who and what is what. It was hard for me - I had such a great R with my F, but I let go and now they know what he is about and live with that.
