It's difficult to determine someone's feelings and intentions with certainty, especially without more context and direct communication. Flirting can have various interpretations, and it doesn't always indicate romantic interest.
There could be several reasons why he's flirting with you despite having a girlfriend and claiming to love her:
He might be naturally friendly and flirtatious with everyone, not just you. Some people have a more playful and outgoing personality that might be misinterpreted as flirting.
He could be unaware of how his actions are perceived and may not realize that he's crossing boundaries.
He might be experiencing some dissatisfaction or issues in his current relationship, leading him to seek attention or validation from others.
He could be confused about his feelings and experiencing mixed emotions.
However, it's essential to respect his current relationship with his girlfriend. If you are interested in him romantically, it's crucial to consider the potential consequences and impact on everyone involved. Engaging in any kind of relationship with someone who is already committed can be hurtful and lead to complications.
If you find the situation uncomfortable or believe that his actions are inappropriate, it's best to communicate your feelings with him openly and honestly. Alternatively, you can set boundaries to avoid any misunderstandings.
Remember that it's always essential to prioritize honesty, communication, and respect in any relationship.