There is this girl that is strongly affecting my brain chemistry. She has mysterious physical and non-physical qualities that my subconscious apparently cannot resist. We are both shy and have not interacted much socially, but when we do I get a strong sense that she is attracted to me (based on intuition and supposed behavioral signals I've read about on the internet). However, I have recently learned that she's already in a relationship. I came here for advice because I don't know how to proceed. I am getting to an age where I need to soon find the right girl to eventually marry and start a family with. I want her to be the one, but there are several other girls I have considered pursuing. I'm being careful to choose a girl I really like to prevent wasting time or being in a position where I have to deliberate over whether to break a girls heart in order to get out of a relationship I'm not happy with. I would never hit on her or seduce her knowing she has a boyfriend, but should I flirt with her? Should I make it clear to her that I like her, let her know I am an option? Should I move on? One factor worth mentioning is that our life trajectories are aligned such that we will likely be within reach of each other for several years.