Children are a wonderful gift from God. But children are a temporary assignment entrusted to our care for a season. Never let your children run or ruin your marriage. 

Yes, children are important and God commands us to raise them in the fear of the Lord. But children should not occupy the center of marriage. Marriage is the partnership of husband, wife and God. Children are the fruit of marriage.
Fruit is seasonal. The marriage tree exists before, during and after the fruit is harvested. Some people make the mistake of prioritizing children above their marriage and above their spouses. 

Children are not the glue that binds couples together; God is. If your marriage is held together by the children; what will happen when the children are gone. Ensure that your marriage lasts after your children are gone. Spend time building your marriage while your children are still there. 
The most loving thing you can do for your children and step children is letting them know that their rightful place is below your spouse, not above or between you and your spouse."