My brother and I were having sex on the living room sofa, which faces the door. It would have been so exciting if my husband had suddenly...

My brother and I were having sex on the living room sofa, which faces the door. It would have been so exciting if my husband had suddenly come home! Luckily, that didn't happen. But lately, it seems my brother's been exercising more; his stamina isn't what it used to be. I wonder if I've drained him dry?