This is dumb beyond words. First, because it indulges in that whole idol purity bullshit as the biggest roadblock for Kirara. Oh my god, she had sex! Now she can't sing and dance anymore! Oh, wait. No. Turns out having sex doesn't rob you of your musical talent, it just makes you unpopular to weirdo purity-worshipping incel losers who can't cope with the idea that a person they like in a creepy parasocial way has a life outside of them.
Meanwhile he's going to be her manager, something the actual boss doesn't want and actively opposes, but somehow what's going to convince everyone to let him have the job is that he's setting conditions for his acceptance (which is silly considering you normally only have the leverage to set conditions when you are desired for the job, not when you're begging for it) two of which are a) I need to find out if I can even do this without getting fired from my real job and b) I need someone to teach me everything about doing this job that I just recklessly signed up for.
And then all of this is for the photos of him and Hebo, which he needs because he wants to marry her? That basically makes the photos irrelevant. Because 1) the photos get out and she would presumably stop being an idol because of the aforementioned purity bullshit or 2) the photos don't get out, but they would not be able to marry while she was an idol because of, again, the aforementioned idol purity bullshit. It's laid out directly in the second chapter that she would have to "graduate" before marrying.
They need to do this because it's the only way to maintain the drama and tension that the story requires outside of just focusing on the two of them getting to know each other, but it's so silly and artificial that it makes me not give a crap.