How can I deal with my feelings towards another young man and my desire to marry him, given that I am married and have a child, and what is the way to get out of this situation?

Your relationship with this young man is a great betrayal and a grave sin. You must cut ties with him immediately and repent to Allah. You should strengthen your relationship with your husband and be patient with him, especially since you have a child together. To help you forget this young man, remember that he does not want you as a wife; rather, he desires what is forbidden, and he is a betrayer of his religion and his honor. Therefore, you should detest him. Turn to Allah through supplication, asking Him to remove him from your thoughts and to instill love for your husband in your heart. Remember the immense right of a husband; the age difference is not a significant impediment in marriage. If you cannot live with your husband, you have the option of khul‘ (divorce initiated by the wife), but do not accept that young man as a husband until he repents and becomes righteous, and wait for a man of religion and good character.