My marriage ended badly, but my ex-wife's father was always kind to me. He taught me practical things my own father never had the chance to teach me.
Once a year, usually around his birthday, I visit him. My ex-wife knows and apparently doesn't mind, but we never discuss it. He and I drink tea and talk about ordinary things. Divorce ended my marriage, but I couldn't accept that one legal separation had to erase every relationship built around it.