My girlfriend develops feelings for a colleague

I am a 27-year-old with a monthly income of VND20 million (US$811), while my girlfriend, who is younger, earns a monthly wage of VND10 million as an office worker.

Her family is financially better off than mine, with her parents still young and actively working. Meanwhile, I share my home with my ailing mother, who engages in household chores and small-scale home sales for additional income, and a younger sister currently enrolled in university, following my father's demise due to illness.

We have been in a relationship for four years, experiencing its fair share of challenges and triumphs. My affection for her began when I was still finding my footing professionally and she was a student. Recently, our relationship has been relatively stable, though not without occasional disagreements and personality clashes.

She is meticulous, organized, and sensitive, contrasting with my outgoing, inattentive nature. I am also often preoccupied with work, personal pursuits, and entertainment. Despite these differences, our love for each other is strong. We communicate daily and meet at least once a week, make plans for the future, including my creation of a comprehensive financial strategy for our prospective home. She inspires me to strive for betterment daily.

The past two months have seen us both engulfed in work and her studies, reducing our communication frequency. During our conversations, she would speculate about the implications of a breakup or the possibility of either of us finding someone new. My laid-back attitude and belief in her unchanging affection led me to respond to her inquiries lightly.

However, she eventually declared her exhaustion with our relationship and her wish to end it, prompting me to request time to reignite our spark.

In this period of absence, my longing for her persisted, leading me to continue sending messages. She confided having developed feelings for a colleague who exhibits the thoughtfulness and understanding she values, clarifying that these feelings were purely contemplative, without any actions taken or intentions of pursuing a romantic involvement.

Upon her acknowledgment of this mistake and her desire to resume and rejuvenate our relationship, I reacted with anger, despite recognizing my own neglect and resistance to adapting to her needs as partial causes of our predicament.

What should I do now?