I don't quite get your point, to be honest. How is a male love interest as an additional option any problem? It's not NTR. I do understand your issue with NTR and common execution of it and i agree. i just don't see how it's related to "let's add a completely optional piece of content" like male love interests.
I do think anything that is unexpected or extreme (non-consent, young-appearing characters, various queer stuff, hard kink stuff, foot fetish, whatever unusual thing people are sometimes into) can be ruining the mood for the player if it is not what they expected to come across.
If labeled appropriate and thus avoidable, there is no issue at all.
One AVN had a "blackmail suspect" option to help solve a murder case - but it got unexpectedly extremely rapey and not at all what i expected (or wanted in that scenario).
I found that really off-putting, because it just came out of nowhere.
Similar to what you describe with NTR.
Other games do that better by allowing pre-emptive decisions in the settings or by clearly labelling implications of decisions if they are out of the ordinary.
If that is done, everything is fine, in my book.