I saw a comment pointing out that MC's in "polygamy settings" don't confess his love to his harem members, well they actually do. Not sure what harem manga you're reading but they must be horrible though.
As for in light novels, I've read 'plenty' fulfilling harem stories and they love each every girl they marry. I recommend Martial World, for starters but It's a long one so maybe start with Stellar Transformation or Coiling Dragon however those are non-polygamy but one of the best chinese light novels out there, that's fully completed and translated.
If I knew chinese fluently I would spend my free time only reading chinese fantasy novels all day long, incessantly.