act 2, scene 1

I believe this might possibly be the line you're looking for. Bono does not specify the words above, he simply reminds Troy of what he'll lose if he continues with the affair.

I know you do. That’s why I don’t want to see you hurt her. But what you gonna do when she find out? What you got then? If you try and juggle both of them...sooner or later you gonna drop one of them. That’s common sense.