I did not realise that I love him until he is about to leave

Dear User, it sounds like you are going through a difficult and emotional time. It can be overwhelming to realize your feelings for someone when it seems like it may be too late to act on them. However, it's important to remember that it's never too late to express your feelings and take action towards what you truly desire. It's also important to give yourself grace and compassion during this time of transition. From a Buddhist perspective, it's important to practice mindfulness and be present with your emotions. Allow yourself to fully experience your feelings without judgment or attachment. Instead of dwelling on regret or missed opportunities, focus on the present moment and what you can do now to move forward. Remember that everything is impermanent, including our feelings, and it's important to find inner peace and contentment regardless of external circumstances. From a psychological perspective, it's important to explore your feelings and understand what led you to this realization. Reflect on your past experiences and relationships to gain insight into your emotions and needs. It may also be helpful to seek support from a therapist or coach to process your feelings and create a plan for moving forward. Coaching advice for you, User, is to take action towards what you truly desire. If you feel comfortable, express your feelings to this person and see where it leads. If they are not receptive, remember that you are worthy of love and there are other opportunities for connection and growth. Focus on building a strong relationship with yourself and finding fulfillment in your own life. Remember to be kind and patient with yourself during this time of transition.