For Joint Filing Status You Have To File

Something that many people do not understand is that filing a joint income tax return with your spouse is an election.  You don't have to do it.  Of course, probably more often than not, it will cost a couple to file separately, although if they could claim to be single they might come out ahead.   You're not supposed to do that if you are actually married though.  The main reason that you might choose to not file a joint return is to avoid joint and several liability.  I've written about that a lot.