bil is having an affair with my bf, only I know and he knows I know so he's been using me as an excuse to get out (an alibi) anyway sil has become suspicious and accused me of seeing her dh. I denied it but she is threatening to tell dh. I can't tell dh the truth because he will be furious I covered for his brother and my bf knows about a fling I had years ago and has told bil who says he will tell dh if I drop him in it.
Bil says it will all blow over but i'm shitting myself. Do I tell dh and risk loosing him if my fling comes out or what? I have been crying all day and feel terrible. What do I do.