If you "have to be involved" does that mean your husband should not have custody? Because if you "have to". What would happened if you didn't do it? Would he fail as a parent? Would he leave vital things undone? Would he allow his kids to be... Whatever.... Uneducated, uncared for, abused, undisciplined, failing at school... And if he DID allow those things, why would he have ANY type of custody?
Do you consider your husband a capable parent? I do. If I were not involved, he would be fully capable of parenting. Now, there are things I do better than him (planning, scheduling). But I don't "have to" do those things for him. If they caused problem, especially problems for the kids, , I would not do those things for him. Because he IS capable and deserving custody.
Personally, I think when a sm says she "needs to be involved" and goes around her husband, she is diminishing his role as an effective parent and trying to make herself more important. Essentially, she is saying he isn't a very good parent and should not have custody because he cannot parent.
I can't imagine my husband saying he "needs to be involved" to my ex. My ex would think he was stupid. So I would never say that to bm, or the court... Or this forum.