Your relationship with money is often a reflection of who you are as a person and how you interact with the world.
If you are by nature cautious, you will probably be very careful with your money. Likewise, if you are a go-getting risk-taker in life, chances are you will take risks with your money.
The way in which money is managed within a relationship often reflects how committed the relationship is and how the two people concerned have dealt with their individual differences in their relationship with money.
There is a continuum of possibilities for managing money in a relationship. Bad experiences with former partners can cause people to be cautious and keep their money separate.
A big difference in income between two people can have an influence as well.