Is the supplication of the questioner when she was young, that she would not marry except a suitable husband, and if not, then in the Hereafter, the reason for her not marrying until now?

These obsessions and thoughts are satanic, aiming to instill sadness, so you must rely on Allah and seek refuge in Him from Satan. Your supplication was not the reason for the delay in marriage; rather, it is a trial from Allah to test your patience. Marriage is a provision that will come to you as decreed, so turn to your Lord and ask Him to facilitate a righteous husband, and seek help from trustworthy individuals in finding him. If there is a strong suspicion of magic or possession, you must resort to legal ruqyah (definition).