Idk why people keep saying this. Harem manga has changed since the early 2000s there’s honestly no ongoing harem manga with this plot-point or things that you listed.
Hold on everybody that's about to drop the series. Let's give it, at Most 3 to 5 chapters, and if the MC is still getting Cucked without any sign of a redemption or payback, THEN Drop the series. It's too early right now, the pay-off might be the biggest dopamine release In your brain.
We must of been reading two different stories then. Because its absolutely meant to be romantic, just because he helped her get through the pain, doesn't mean It's platonic. They could've been married and had kids if he hadn't died. You to be wife is basically family.
The MC isn't really different from your average OP protagonist.
And her motivations from the beginning of the story till now doesn't really strike me as anything interesting and worthwhile.
Honestly I'll give this manga a 5/10 right now.
There's nothing really unique about this story so far