Unless you and your live-in lovah are perfectly compatible, you will fight about money at some point. Some couples find the common practice of sharing the same accounts to be suffocating and appreciate the relative freedom of maintaining discrete funds.
A Women’s Money Week post argues the virtues of keeping couples’ funds separate. The writer says the setup forces both partners to learn to be accountable and responsible with money and can make each person feel more comfortable about making financial decisions without clearing them with the ball and chain, reducing the amount of conflict.
The downsides come in deciding how to distribute the household’s collective income if one person makes a lot more than the other, as well as determining who pays which bills. There’s also the potential for financial abuse, if one person makes all the money and only metes out a small allowance to the jobless spouse.
A Case For Maintaining Separate Accounts [Women's Money Week]