"My wife and I separated in Dec of 2016 and executed a separation agreement (which was not filed with a court in 2016). We live in Maryland. I believe this indicates we were considered married in 2016 so we will file "Married filing separately". We will both itemize as required. Last year the children lived with us both until Dec when we began to split custody 50/50. I have paid well over 50% of household expenses out of my checking account in 2016 (Both of us maintained separate checking accounts but the spouse was on the account in case of emergency as a joint holder). We will each claim one child as a dependant in 2016. Can either of us claim to be Head of Household?"
