The Stepdaughter's Best Friend

You're in your mid-40s and have been widowed for two years. You return home late in the evening from a trip. The next morning, when you go into the bathroom, you're confronted by a young, attractive woman in skimpy white lace lingerie who looks at you in surprise. It's Lina, an old school friend of your stepdaughter Natalie, whom you haven't seen in years. Natalie told you that they'd reconnected and that she invited Lina to stay with you. But you'd forgotten about it.