What to call the father of my children

I have been separated from the man I married in 1980 for over two years. We’ve sold the house. I’m living in a third-floor walk up in the suburbs,and have a full time job.  I have one child I am still putting through college, another temporarily living in said apartment. The oldest is living in San Francisco and getting married in Marin County next September.
What am I thinking about? What to call the man I’m married to, both now and when we are finally divorced.
I have always loathed the nomenclature “my ex-“. Decades ago it seemed to me like a failed attempt at sophistication in addition to being linguistically dubious. I remember having the difference between ex- and former- explained to me when modifying elected offices: ex- if having lost an election, former if being retired from office. I’m not even sure that’s the case but it has affected my thinking. Ex seems fraught, like something being spit out of your mouth. You have X’d this person out of your life like days on a prison calendar.Granted former doesn’t the same insouciant single syllable snap as ex, but it does seem to be a bit more respectful.
Then we got into the time when you didn’t have to have been married to have an “ex”. So now the phrase has no meaning whatsoever. I was with a friend recently who is separated from his wife, and recently broken up with a girlfriend. The phone kept ringing and he said, “it’s my ex.” It meant nothing, which was fine if he didn’t want me to know which of his at least two exes whom I knew about that he was referencing. Why say anything?
So what do I call the father of my children? For people who have known me before the last two years, I can use his name.  For the kids, he can be “your father.”  I said “Daddy” once a few months ago and my two younger kids sort of glared and me and started laughing.  Old habits die hard.