Is it permissible to marry a widow who has children and is older than me, without my parents' knowledge, but with the knowledge of her elder brother, and with our agreement that I travel to her monthly, and given the children's affection for me, and the possibility of my marrying another woman to please my parents?

There is no objection to you marrying this woman without the knowledge of your family or her deceased husband's family, if her brother marries her to you in his capacity as her guardian, and two just witnesses attest to that. It is preferable for the marriage to take place in court. We draw your attention to the fact that acquaintance between foreign men and women for the purpose of marriage can be a door to temptation, and she is a stranger to you as long as you have not contracted marriage with her. Therefore, it is not permissible to be alone with her, touch her, or be lenient with her in speech. We advise you to consult with wise people and perform istikharah before proceeding with this matter.