All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
If this man is religious and virtuous, you should accept him as a husband. In a Hadeeth (narration), the Prophet, sallallaahu ‘alayhi wa sallam, said: “If there comes to you a man whose religiousness and morals you approve, then let him marry
[from women under your guardianship]; if you do not, there will be Fitnah (temptation/ trials) on earth and widespread corruption.” [Ibn Maajah]
A religious man is one who observes the religious obligations and does not commit grave major sins. You should perform the Istikhaarah (guidance) prayer and consult those whom you trust from among your family members as well as other righteous people.
If you marry him, you should constantly supplicate Allaah The Almighty to cure his sterility and pay no attention to what the physicians say that his sterility is incurable. Allaah The Almighty cured the sterility of the wives of His prophets, Ibraaheem (Abraham) and Zakariyya (Zechariah), may Allaah exalt their mention, even though they were old and sterile women.
We ask Allaah The Almighty to relieve your suffering, make your life easy, reform your condition and guide you to what is good.
Allaah Knows best.