Some additional finer points on the usage of "anata" as "dear" or "honey... as the way I understand it... ^^
* When used in this context, usually it's used between married partners, and by wife, but usually
not by husband. In that sense, when used in this context (used when a wife is calling out to her husband) it basically means "Husband" or "you," and if she is using the word in "endearing/affectionate/sweet" tone, then more or less you can probably interchange the word with "honey" in English and you can probably guess the nuance of this word in this usage in this tone.
* The above usage is usually NOT common by a couple who are "just lovers", unless they are already living together and in practical sense, in a "common-law-husband-wife" relationship, etc.. Of course they will use the word "anata" between them just like anyone and everyone in the context mentioned below, and naturally, them being lovers, it is likely that many times the word may also include some degree of sweetness/affection in it's tone, but not to the extent of the word being in the context explained above, and if a couple in love, more specifically, "a female part of the couple who are lovers but not close enough to the extent that such usage is mutually accepted by both partners of the couple" uses the word in the above context, that may "jolt" male partner of the couple xD and if such female would use the word in the above mentioned context IN PUBLIC situation such as a couple who are working together in a same office, that may possibly cause scorns among people around.
In that way, it's almost like... in a strange way, it's like a "privilege" for wife (or some female person who is recognized as a person in a similar situation) that she can use the word in this context (as in referring to the person as "husband") when referring to her partner.
...and that's my general understanding of the usage of this word in this context.

By the way, Izemi calls Sig this way practically all the time, except she uses "anta (pronounced ann-tah)" which is more casual form of 'anata," and more or less equivalent of "hon."
However, please note that wife also uses the word "anata" when talking to husband (or when referring to her husband in "2nd person form")
as a regular non-endearing form of "you," just like anyone. Hence, just because a wife calls her husband "anata" that does not necessary mean that was in the "endearing/affectionate/sweet" context mentioned above. (For more usage restricition info on "amata" as "you", please read
my post on the next page.

)
THEREFORE... I don't want to throw cold water over anyone who may get overly excited over Riza using this word when referring to Roy because the same word is also used by wife when referring to husband in "endearing" context, and yes, it is out of her normal mode that she is not referring Roy by his title/rank, and hence this is more "personal" way of calling/referring to Roy, but jumping into the "fantasy-world" and connecting this directly to "wife calling husband
anata in endearing/affectionate/sweet mode" maybe a bit over-simplifying XDDD (not that I see anyone doing it, but just as a precaution. XD)
Rather, to me the significance of this is, it exhibits their EQUAL relationship, not as a mere superior-subordinate relationship. And, I like that.