he captures my heart

The guy that you are having feelings for is already taken. If what you're feeling is just a simple admiration, I don't think there is anything wrong with that. But if you feel that you are really falling for this guy, I would suggest that you don't do anything about it. I'm sure you wouldn't want to cause anything that would hurt their relationship.

The most important point in your statement is someone's holding his heart. You should try to think about how it would feel if you're the one holding his heart and someone else fancies him or is doing something about it. You will not appreciate it. There will always be people that would feel 'right' for us, but not all of them would be the 'one' for us. Just try to respect the people that love. Don't allow yourself to be attracted to someone who is already attached, I tell you it's not worth it. Don't worry, soon you'll find that special someone who would make you smile more, not for the mean time. When that time comes, he will be right and made just for you. Good luck!