Sally and Mike are a married couple. Their combined income for 2018 is $48,324. They have a son, Mike Jr., aged 9, and a daughter, Tina-Marie, aged 6. Both children attend after-school care at the cost of $1,800 per year. Seven months ago, Sally and Mike had a huge fight and Mike moved into the guest bedroom. The couple barely speak and keep different hours. Sally told her best friend that it's as if Mike is not even there and she has decided to get a divorce. She also noted that Mike does not help out with the kids.

• Discuss Sally and Mike's filing requirements and filing status.
• Is "considered unmarried" an option? Why or why not?