Murakami can admittedly come off that way. But if you observe her, the only time she's really upset with Moritani is when she freezes time for someone else with no warning, which robs Murakami of her chance to enjoy time where she can just be herself (which we learn is very important to her in the final chapter) and freely interact with Moritani.
This whole time the manga has presented the pairing as slightly unbalanced or uneven, with Moritani idolizing and obsessing over Murakami, when Murakami may have actually been even more infatuated and obsessed with Moritani for a long time.
Oh, like someone requested, half of the last chapter recaps all the major events of the manga from Murakami's PoV.