I call my ex-husband my co-parent and my wasband.
Co-parent is the term I prefer over single mom or baby daddy. I’m a co-parent. He is my co-parent.
I don’t like ex-husband. It has a negative connotation to it. It implies that we are in conflict and that really isn’t true anymore. We were in conflict when he was my husband. He was my husband. Wasband.
“My kids’ dad” is too wordy and awkward. It might imply also that he’s not in the picture. He’s in the picture.
His primary role now is not in relation to me, which ex-husband implies. His primary role is in relation to our shared children. In other words, he’s their parent. I am their parent. We are parenting together. We are co-parents. We’re sharing time and sharing responsibility.