the boyfriend

let me tell you a story. it involves A,B, and C.
A has a big crush on B. For many reasons, it is a one way sort of deal. Now, A finds out that B has a boyfriend, C. He actually meets C, this is how A finds this out. Then one fateful day, A enters the building where he and B see each other regularly (about twice a week.) And who does he find waiting for B? none but C. So he sits down and starts talking to C, and has a lovely conversation, about nothing in particular. Then enters B after about half an hour of A and C's conversation. A does not see C for a long time, and eventually does not see B for a long time too. But not because he isn't trying, as A often tries to find excuses to contact B. And one of these reasons is a "wait, you're single now? what happened to C?"
After months, C contacts A. The two communicate very often, and A starts to feel like C might have some sort of feeling for A. However, A doesn't really feel like that about C, and starts to feel bad about B and not telling C about A's feelings for B. So A puts it behind him.

Now, what is the worst, most Shakespearean thing that could happen?
The worst possible scenario as follows: B told C to save him from A and this is how C got A to leave B alone...