You may be able to win the battle and the war. The battle is, of course, whatever dispute you are currently having with your ex. The war, is the struggle for your longterm happiness.
Think about whether winning the battle truly fits into winning the war, or whether it will lose the war. For example, if you are being unreasonable and attacking your ex with everything you can imagine so that you can win child custody away from your ex (and in your heart of hearts you know you are in the wrong), you could, by fighting this battle tooth and nail, end up losing the war over the hearts and minds of your children.
You may not even know you lost that war until much later when your children move far away and do not invite you into their lives. You may not attend graduations, birthdays, weddings, and other momentous life events. What is more, when you arrive at the winter of your days, your child either completely ignores your needs or places you in the worst home they can find. This is when you know you lost the war.
When dealing with you contentious and emotional child custody battle, consider becoming more stoic and reasonable. Consider conceding the battle to win the war. Do not sacrifice your entire future for the satisfaction of the present. Moreover, you may lose both the battle and the war. Don’t do that.