I call her by her name. I have used "baby" once, but I didn't like the sound of it and I cannot really pull it off. I don't have the appropriate voice to do such a thing, my tone of voice doesn't change. She agreed with me by laughing.

Oh. I've used "DAAAAAAAAAAAAHLING" once or twice. She liked that a whole lot, it makes her giggle. I only do it playfully though.

I adore her name, so I use that most often.