I started writing the 10 Foundations of Personal Finance last year and I am finally getting around to posting the final one!
If you have a spouse, partner, or significant other you have to be aligned on the first 9 foundations if you are going to be successful. Money disagreements are one of the biggest reasons for divorce and separation today. I have seen so many relationships where you have a saver and spender getting into constant disagreements over money.
Now I am not talking about having perfect alignment 100% of the time. There is always going to me some variances, but the key is that you share the same core beliefs on money and that you are aligned on your long term financial goals and the path to achieve them.