It's a pretty repetitive manga, the "relationship" develops to the point where it's starting to happen something betwen them, but like all the generic mangas, it gets stuck in that in tons of generic chapters.
No romance or story development at all (this hardly deserves the romance tag), just boring big boobs jokes, one after another.
To make it short: No actual romance, no story development, no character development, just tons of generic manga chapters with boring big boobs jokes.

I'm kinda regret due to reading that manga, it's full waste of time. I got a one thing from that manga is solely big titty office lady and unfunny perverted jokes.

Sadly to no one's surprise, the female lead is mostly just depicted as walking tits and all the jokes evolve around his breasts. Either in the form of office sexual harassment, misunderstandings, innuendos, and mild romance/sexual tension between our leads. It wouldn't hurt to have other jokes/situations mixed in to give her more depth besides her depicted laziness during her time alone on holidays.

It doesn't help that our female lead is extremely sexualized with pinup shots of her between chapters. The author definitely has an agenda: "Tits are fun!". She's also a unicorn: Mature woman with a model-like body who's still a virgin, a mild Otaku, and with a diet that defies her tiny waistline.

Given all of this, this story and the jokes are all very 'flat' and I wouldn't recommend this unless you're all in for mild ecchi office lady panels.