Pressuring someone to have sex is not saying "I love you."
It is saying "I love me."
Sex is not leverage. Affection cannot be bought. It does not matter how much time someone has spent with you or how much money has been spent on extravagant dates. The four-course meal and dessert they purchased for you is not a free pass to dishonor you as a person. You don't owe them affection. You don't owe them sex. Affection given out of obligation is not true affection. You and your body are too valuable to be given away in exchange for a nice meal.
You are worth having your boundaries respected. If someone is not willing to respect your boundaries, then they do not see your true worth. You are worth respecting. Don't let someone's inability to see your true worth determine your value.