My boyfriend likes to be called "daddy"?

Last night my boyfriend and I were getting down with it and I asked him to dominate me. He's always been very gentle with me, like gently pulling on my hair and pinning my arms down (that's our version of domination). However, last night, in addition to the hair pulling and the arm pinning, he suddenly got really into it. He went almost animal with it and let out this big groan and then said "Who's your daddy?" It honestly surprised me because it's the first time he's ever said that and we've been together for more than a year. After me calling him "daddy" he went more aggressive with it (not in the way of hurting me but like his inner man beast or whatever was released). When I was young I was sexually abused by my dad and while it doesn't feel awful to call my boyfriend daddy, it feels weird to me. I'm worried that if I call my boyfriend "daddy" then I will associate him with the abuse I endured when I was young and I don't want that to happen.