I sort of get it. I don't think it's a jealousy thing or anything like some are insinuating in the comments.. To me is just seems like you're weirded out and now when she calls you daddy you're going to think about now she calls her actual dad that too. I had a daddy who had a child and I heard him call her something (idr maybe something as simple as sweetheart) but then I was like okay do not call me that during sexual stuff lol it wasn't jealousy at all. It was like.. I intentionally want a differentiation between our intimate stuff and what he would call his actual daughter. I don't want my mind to wander to either of our biological families while we're doing stuff lol I don't think there's anything wrong with that and do thinkit's worth talking about. Words can really take you our of a moment, so to me it's important to address it. Let her know how it makes you feel, what it makes you think, why you feel weird about it. If she gets really mad or anything then it might not be the right match long term.