For my situation, it's kind of like the pp suggested, but in reverse. My son's father is Russian, so DS has grown up calling him "Papa." So now that I'm getting married and my fiancÚ has lived with us for the past 1.5 years and been in our lives for 2 years, DS calls him "Daddy." He started calling him that exactly a year ago. It was his choice to call my fiancÚ that and while I didn't discourage it, I didn't encourage it either. My family has had a hard time with it because my ex is still in our lives, but as I've told them many times, it was up to the child and we need to look at reality here: my fiancÚ is in our lives for good - this isn't a passing fancy; he is more of a father than DS's biological father has been in the past 2.5 years; calling him "Daddy" doesn't negate DS's relationship with his biological father; and to have DS grow up calling the most present male figure in his life by his first name is awkward. I mean really, when we meet people, what is DS supposed to say?..."this is my mama and this is my Ryan?"
For us, it happened quickly because my fiancÚ and I knew very early on that this was it - we had finally found each other and we were meant for each other. If there'd been any doubt in my mind, I would have waited a long time before introducing my son to him, or moving in with him, but that's not how it worked for us.
Working mama to Peanut #1
(7/06) and Peanut #2
(10/11), and future wife to the most incredible man I've ever met!