I think originally is meant to say “ai-chan”, because it’s meant To be endearing, but I’m not sure why they didn’t keep it that way u.u
Akihiko calls him "Ai-chan", you can see that in the first and second chapters. After that, the chapters are the official translation – in which they often localize things like honorifics because they don't exist 1-to-1 in English. So "Ai, love" is the way the publishers found of translating "Ai-chan", and although it doesn't really mean the same, it's the best they could do without completely scraping the honorifics altogether (like they did with Ai, who calls Akihiko as "Akihiko-san"). "Ai" also isn't used as a term of endearment though, so it'd be quite awkward to translate "AiAi", as a nickname, into that (although it'd depend mostly on what kanji is used for Ai's name I guess). The best way it could go would be for Akihito to just be kinda awkwardly redundant and say "Ai, anata", as "anata" is a "sweet" way of refering to someone (would substitute omae, kimi, anta, etc and translate to "you") and is the closest thing to a term of endearment in Japanese (not counting "daarin" and "hanii", which are just the words "darling" and "honey").
I could be wrong but does Akihiko call Ai, 'Ai-ai' like a personal nickname for him, which is why the translation goes with 'Ai, love'?
Bc ain't no way he'll call him love in public, like the one on the company event lmaooo