Understand his interests and passions and incorporate them into your interactions. For example, if he loves a certain sport, plan a related date or activity.
Good communication is key. When a husband and wife communicate openly and honestly, they are more likely to understand each other's needs and be satisfied in the relationship. Also, spending quality time together, like having regular date nights, can keep the bond strong.
Seducing someone else's husband is not ethical. It can lead to the breakdown of a marriage, causing a great deal of pain and emotional distress for the wife and potentially children involved. It also violates the trust within a relationship.
That's an unethical situation. But here is a fictional one. There was a couple, the husband and wife. They had a friend who was very naive. They started by inviting the friend to a lot of private parties, dressing more alluringly around the friend. Eventually, the friend realized what was going on and cut off the relationship as it was inappropriate.
She can cook his favorite meal and serve it to him in a sexy way, like wearing an apron that shows a bit of her charm. Also, she can give him a massage, using scented oils and soft touches.
Be patient. Rushing things will only make her more reluctant. Try to understand her needs and interests. For example, if she loves books, plan a date at a local bookstore or a library event.
Seducing a lady in fanfiction often involves creating a charming and mysterious persona for your character. Add in some thoughtful gestures and a slow build-up of tension to keep the readers engaged.