I actually have a really boring story about telling my fiance. He was my boyfriend at the time and we shared a lot of other kinks. I was on fetlife one day and saw something about ageplay. I was very very intrigued. I kept learning more about it. It never occurred to me to be nervous about it, I knew he would accept me no matter what. So I just said, "Hey, I've been learning about ageplay. I was wondering if you'd have a daddy/little girl roleplay with me"