To be honest, my husband and I call each other by name. Since our daughter was born, we call each other ママ and パパ so she understands what to call her parents.
Even when kids grow up and move out, many married couples tend to keep the ママ and パパ title. I used to think it was weird until I realized how quickly you get used to it. After saying it for several years, it probably just sticks.
We still try to use names when we’re talking in private. But for all intents and purposes, I’m literally お母さん with my daughter or 先生 at school so that’s just one way Japanese people lose their individuality I guess.
As for other terms of endearment, あなた is very commonly used to address your husband directly especially in older generations. But not in the same way you use it as just a personal pronoun. It’s more sing-song like あ~な~た~.
Also, my elderly neighbor calls her husband ダーリン, but she studies English, so it’s hard to say if that’s a common thing. It’s more likely among young people. Same with ハニー.
From the man’s perspective, all I’ve ever noticed is the man calling his wife by his first name with ちゃん attached. If they’re really close, he won’t use a title at all.
The most popular way to communicate closeness is the nickname route really. Both parties often shorten their partner’s name and add a suffix for both as well. For example, Sacchan for Sachiko or Takkun for Takeru. When I think about it, my husband and I call each other by nicknames than our full legal names, but we don’t use titles. We’re also not the norm because we run a guesthouse and our guests call us those names as they are simpler.
As for children, again, the nickname route with a cutesy title like ちゃん、くん、たん is common. We call our daughter Tan-chan which is completely different name than her real name, but it’s our inside joke so we use it occasionally at home. Her teachers will often shorten her name and add ちゃん. We also use おいら when we’re narrating her actions from her perspective.
