I have two ideas here.
Girlfriend/Boyfriend's best friend
Kathy and William had been going out for years and they decided to tie the knot, although William's best friend has something to say about it. He has had his eye on Kathy for sometime now and he is determined to have her. So when William is away on a business trip, He pays her a vist. (He could pay her a vist at her house or at work)
He has never learned the meaning of the word no, being from a rich family he pretty much got anything he wanted. So why does this Nurse think she can tell him no. The nurse is about to learn the punishment for saying no to him. (This can start out as NC but then turn to acutally him falling in love with her as she is the first person to stand up for him)