Kasumi has been hooked on dating sites since long ago. She can't be proactive in love because she's afraid of being dumped, so she seems to have been casually dating multiple men. The reason she continues to use dating sites even after marriage is that she wants to be prepared in case her husband cheats on her, indicating a rather twisted view of love. And it seems her husband's infidelity has come to light, so perhaps she is feeling quite lonely inside.
