I think I may be falling in love. And that's not a good thing.

It's heartbreaking to watch someone you care about be heartbroken, and yet, when he bears it so admirably, it's so touching you can't help but wish it was you who had the power to do that.
Not that I want to break his heart, but I do wish I could heal it a little bit. He's so unhappy, but still asks me how I am every time I talk to him. He's one of the very few genuine people I know. He doesn't ask the question as a polite inquiry. He asks because he cares about the answer. He listens. He really wants me to be happy - something I gave up on for myself years ago - and his caring makes it feel that much more possible.
Problem: I met him because he was in love with one of my oldest friends - who is the cause of his recent heartbreak - with whom he is still in love, regardless of the fact that she broke his heart. Maybe it makes me selfish, and maybe it makes me a bad person, but every once in a while, I can't help wishing someone loved me enough to be this unhappy because of me. It hurts to watch him be so sad, to talk to him knowing that he's pretending to be happy. Sometimes I just want to sit in a corner and cry over his broken heart. Is that normal?