Man i wanted to be one to comment the 1000th comment but you beat me to itAnd your original point:
Do you undeerstand that the central point here is that: we DON'T know why Iwabuchi loves Rika? And this love is a theme of it's own in the story so far, that wasn't given a proper explanation?
And that, just believing in her words that the kid is his, or she has a good income, have proven to be innefective, with Iwabuchi's look of "jealousy"( as you put it), or Miyabi's assumption that since Iwabuchi has favoritism over Rika, he( most likely), is the source of Momonga's high view counts?
And that, in your 3rd to last comment, you're actually leaning more into talking about Iwabuchi's raw love, instead of it's source( your 5th to last comment)?
And there goes the 1000 comment...
i was waiting for one week