Chances are, you and your spouse don't agree on everything when it comes to your finances. Financial problems are one of the most common reasons for divorce. In fact, according to a study done by Jeffrey Dew at Utah State University, "Financial disagreements...predict divorce more strongly than other common problem areas." It's easy to point to the superficial issues like debt, spending and possession, but those don't really get to the root of the issue. Otherwise it would be an easy fix. So what's keeping you from being unified?
Personality
It could be that one of you is a spender and one of you is a saver. Another match that could cause problems is if you're both spenders. It's important that you know your money personality, and know your spouse's, as well. Doing this can help you understand fundamental attributes ingrained in each of you that make it difficult to agree. You can then focus on things specific to your personality that can help you gain better habits.
Experiences
Many of our habits are largely developed while we are young and impressionable. Our experiences with our parents and friends shape our expectations, desires and, ultimately, our habits. Because they have been ingrained in us for so long, it's not something that can be easily changed - especially not in a contentious setting. A good first step is to take time to think about why your habits are the way they are. Ask yourself if that's the way you actually want to be, or if it's just a product of your early experiences and influences.
Goals
One reason why you're struggling to be on the same page financially is, either your goals are different or you haven't shared your goals with each other. It's important to set goals together as well as to set personal goals that are important to you. If there are no goals or if your spouse does not know what your goals are, your arguments are ineffective because you are focused on the means rather than the end.
Bad Communication
Included in this is miscommunication, lack of communication and selfish communication. The first is generally not the fault of either party. When dealing with the other two, the fault could lie with one or both. It is important to set aside time to communicate about your finances when you are not in the heat of the moment. It is also necessary to have open communication and be willing to listen to each other and consider the root of the problem rather than the fruit. Be willing to be honest, but soften your tone so as to not unnecessarily escalate the situation. Consider if your argument is self-serving and recognize that your relationship is much more important than getting what you want.
Some couples wonder if they should have separate finances, such as checking accounts, budgets, etc. You can do this, but unless either of you is not willing to cooperate, I would recommend combining your accounts and other assets. This gives you the opportunity to work together and become more unified in your relationships.
Budgeting together is also an important solution because it creates an environment where you can set goals together and create a plan to reach those goals. The budgeting session should take place when you are both willing to work together and are open to discussing the above issues.
Financial problems in marriage have a high likelihood of escalating toward divorce. By that same token, a couple who works together to compromise and collaborate on financial issues can strengthen their marriage, grow closer together and establish a good precedent for their children.