You got married when you were both in your 30s, and you were already fairly set in your ways, financially speaking. After all, as a business owner, you'd invested both time and money into your company. You took it very seriously and knew exactly what you wanted to do with every cent.
Maybe your first fight about money was small. Your new spouse wanted to buy something that you thought was unimportant, and you complained. Maybe the next fight got bigger; you wanted to buy a new car for your company, and your spouse thought you should buy a family car, instead. Things just escalated from there, and soon it felt like money was at the heart of every disagreement.