Dear Hadi,
Dear Reader,
You are understandably stressed. When someone you care about undergoes a major change in beliefs, it can feel as though the future you imagined together has suddenly become uncertain.
From an Islamic perspective, however, this is not merely a difference of opinion. Faith is the foundation upon which marriage and family life are built. If your boyfriend has consciously left Islam and embraced atheism, then the two of you no longer share the most important commitment in a Muslim's life: belief in Allah and acceptance of Islam.
The Qur'an speaks directly to this issue. It says: "Do not marry polytheistic men until they believe. A believing slave is better than a polytheist, even though he may please you" (Qur'an 2:221). While this verse specifically addresses marriage, it establishes the principle that a Muslim woman's future should not be joined to a man who does not share her faith. The Quran further states regarding believing women and disbelieving men: "They are not lawful for them, nor are the disbelievers lawful for them" (Qur'an 60:10). For this reason, the classical scholars of Islam have unanimously understood that a Muslim woman may not marry a non-Muslim man.
Since you describe him as your boyfriend rather than your husband, the situation is actually clearer than it would be if you were already married. Islam does not encourage romantic relationships outside of marriage, and it certainly does not encourage a Muslim woman to pursue marriage with a man who has left the faith. Continuing the relationship in the hope that things will somehow work themselves out is likely to deepen your emotional attachment while making the eventual separation more painful.
That does not mean you must become hostile toward him. You can still care about him as a person, pray for his guidance, and treat him with kindness and dignity. People can and do return to faith. But your personal future should not be built on the expectation that he will change back.
For now, the healthiest course is to end the romantic relationship, entrust the matter to Allah, and focus on your own faith and well-being. If he later returns sincerely to Islam, that would be a different situation. Until then, remaining romantically involved with someone who has rejected the faith is not a path that Islam would support.
This may be painful in the short term, but not every relationship that feels meaningful is one that should continue. Sometimes faith requires letting go of what we want in order to preserve what we believe and to trust that Allah's guidance, though difficult, is ultimately for our good.
In peace.