Ex and I split when I was pregnant and he's had no contact with DS, this was his choice. Despite this, over the years we have managed to develop a reasonably civil and grown up relationship, Ex now lives abroad but we exchange very occasional messages and photos.
DS is aware of his birth father, my DH has been in DS's life for more than half of it, and is to all intents & purposes his father, DS certainly considers him to be his Dad.
My Ex will be back in the country briefly to attend a funeral that I will also be at with DS, my quandary is, do I introduce ex to my DS as his long absent father?