The definition of "family" is forever changing, and with this poses some challenges for journalists. When a woman is the mother of a man's child, but they currently have no other legally defined relationship, and were never married, it gets so exhausting to put "mother of his child" in stories. I really wish we could say "baby-momma." Especially when the two have a civil relationship or even a friendship that has come out of co-parenting. They might have dated, but the romantic entaglements are all gone. Ex-wife sounds like there is some sort of dispute. Baby-momma sounds like what it is, baby-momma.
James was joined by his baby-momma for their 7-year-old's school play.
So please, let's bring this term out of the "slang" world and into credible language where it belongs.