Never instill resentment or hate in your children against your spouse. The Court will hold it against you, and it can backfire in a tragic way. That's because if you lose custody, you'll want your spouse to be the most effective and loving parent possible, for the sake of your children. Putting negative ideas in their heads about your partner only makes the job of raising them to be healthy, successful adults harder.
The goal in custody negotiations is to reach an agreement that benefits the children and is livable for all concerned. Unfortunately, issues about children tend to evoke more emotion than other aspects of the divorce process. Finger-pointing and dredging up past wrongs and hurts does not help the process of reaching consensus. So put your anger aside for your children's sake. To punish your spouse by being hardnosed on custody issues may ultimately leave lifelong scars on your children.
Anger is for your therapist, negotiation is for your spouse. Certainly if something upsets you, address it. But be calm, and stick to the issue at hand. Assertive yet courteous is the rule.
To be respectful of your spouse is to be mindful of your children's needs, and their opportunity for a good future.