Parenting: United we conquer, divided we fall...
Perhaps conquer is a strong word. As parents we do not want to conquer our children, but we DO want to overcome certain things that arise throughout the more challenging aspects of parenting. When two parents stand together, united and in support of each other, it gives the children a sense of security and safety. Does that mean Mom and Dad have to agree? No, it does not. But what it does mean is that they must know HOW they're going to agree about disagreeing! I know, it's a mouthful. The simplicity of it is this. Support each other in front of the children, take your concerns and differences of opinions on parenting to a private conversation. Partners are supposed to have each others back, not tear them down and tell them they're wrong in front of their children. The exception I will make here, and it's a BIG EXCEPTION is if children are in the presence of physical, verbal or emotional abuse. It is absolutely a parents responsibility to protect and remove the children from what is happening.
By supporting each other, we model for our children healthy relational habits. It creates a sense of a strong family unit and eliminates confusion for the kids. They might be confused on your the position you're taking, but they won't be confused as to why mom and dad are undercutting each other.
If you're a young family, take the time to talk about your differences in parenting styles. How will you handle the moments when you don't agree? What are some of the issues you can envision that might be a problem? Please do not kid yourself, the list is long. Bedtime? Homework? Religion? Allowance? Dis-respectfulness? Friends? TV / Video games? Have an open conversation around what you might anticipate and how you can approach these things (and more) together.
What do you do if you're not a 'young' family and you have already established the ugly pattern of not having your partners back? STOP IT! What you are doing is harmful. Be the adults that you are and figure out how to change your behavior. Don't wait until the issue is about to explode. If you see something that needs attention, go to you partner and ask how you can both handle it together. If you're unable to shift or your partner is unwilling, get help from a professional.