No, I mean in the manga it is heavily implied that Rudy's actions during beastperson mating season officially made him their fiancée even if he isn't really aware of it right now.

Also I have been spoiled by comments in the manga releases, this is a harem harem and Rudy fucks around a LOT more than his dad did. Roxy is one of his wives.

Also also some series work better as a LN/WN because they are entirely dependent on the MC's inner monologue to develop the story rather than simply show it. Mushoku is kind of half and half which makes the manga a pretty good way to enjoy it since it can dip into Rudy's inner voice to express his struggles with his previous self in the life of his new life without becoming over indulgent in the exposition.

In other series that are multimedia the stories vary greatly between the various versions. GATE is a good example where the LN, manga, and anime all depart from one another. In GATE, other than characters and certain core story elements, the three versions are all distinct from each other. Tone, presentation, narrative elements, and even details change between each version. In my opinion, having read the LN, watched the anime, and currently reading the manga I have to say the manga version is best as it balances character development, action, and the political and military minutia better than the raw autism of the LN and the almost flippant nature of the anime.