“What do you do if you know someone who makes you extremely happy just by their presence and it feels like they’re built to make you happy, but then you realise that you’re not built to be the one that makes them happy?”

I think we’ve all felt this at some point..

I guess the most you can do is hope that they find someone who makes them just as happy as they make you. 

And yes it sucks that you can’t give them that. But if they truly make you happy, you’d want them to be happy first before anything else. Regardless of the circumstance.