I'm doing a study on David right now and they were comparing David and Saul, asking what made David more of a man after God's own heart. Both Saul and David committed great sins against God (you can read about both men in I and II Samuel). The difference is that Saul's heart had hardened against God in his sin and David sincerely repented to God of his sin. The condition of our heart prepares the path of our lives. We are all going to mess up in parenting and in marriage. The way you handle those mess ups determines the way God is going to help you. Spouses and children are awfully important to us, just as Israel was to David. We need to follow his example of seeking God for wisdom and being obedient. If we are not obedient we need to repent ASAP.
So, If you lost it with your husband or children today and spouted off horrible things to them, you have not damaged them for life or ruined you marriage. Just ask the forgiveness of God and of them and God will bless that which you have been so richly blessed.