The context (Kawakami literally just left his house, now someone is calling him over) strongly implies he's cheating on her, and I'm not sure your rewrite is coherent (What? She leaves his house, then immediately invites him over? Why?)
The ending was indeed rewritten because I have noticed from ***** everyone hated that it implied he is cheating on her, however the rewritten ending does not make sense since there is a sequel to this doujinshi