How should I deal with a romantic relationship that lasted two and a half years, transformed from strong attachment to aversion after I asked to stop discussing sexual matters, and despite my aversion, the other party's attachment increased, and I am now uncomfortable and cannot go back to accepting this relationship?

These relationships between young men and women, in the name of love and marriage, are a gateway to evil and corruption. They contravene the guidance of Islam, which protects women. If these relationships lead to abandoning prayer, then it is obligatory to hasten to repentance by severing the relationship with this young man, abandoning the sin, regretting it, resolving not to return to it, diligently performing prayers, striving in obedience, seeking righteous company, and frequently engaging in remembrance (dhikr) and supplication (du'a).