Love @ the office drama.

Person A (I will call him Jack) is a 28 years old junior associate at a consulting firm in New York (but that’s not essential information). He is single, and he fell in love with Miranda two years ago.

Person B (I will call her Miranda) is a 30 years old senior associate in the same consulting firm (thus, on selected projects, she is Jack’s boss/supervisor). She is living a 10 year relationship with her boyfriend (he’s 3–4 years older than her), so they’ve been together since she was 20 and they moved to live together one year ago.

Jack and Miranda started to work together a couple of years ago. For Jack it was love at first sight. She knows it because last may he got completely wasted during the firm’s retreat and he revealed his feelings (but that’s another story).
In these two years they got very close. She tries to assign him in all her projects, and when they are not working together she calls ¾ times per day (just to know how he’s going, or so she says). They obviously started texting and e-mailing. He replies all her calls and messages, but it’s kind of weird since many (if not all) times the conversation turns on their relationship and he knows she has boyfriend and they live together.
Miranda acts strange. She is jealous of Jack, she worries if he doesn’t reply her calls, she always wants to be close to him but at the same time she avoids talking about her feelings for him. (e.g. Jack asked her many times what does she exactly want from him and she wasn’t able to answer). She says Jack understand her better than anyone else and that’s why she is always looking for his point of view. She texts him in the middle of the night saying that she’s missing him when they don’t see each other, but she always stops one or two inches before the line that separates ‘colleague that became good friend’ and something more.

On the other hand, Jack loves talking with her and discovered she is a really good friend to have beside. Of course he hates this situation and he would love something more but he feels that acting (in either way) may ruin something beautiful.

Next week they are heading to London together (they will stay there a couple of weeks for a project).

What is Jack supposed to do?