Dude....if you want to have a shot at saving your marriage do not tell anyone. If you want it to end and speed up D then tell. The irony is that she will never trust you again. You also never know her sister may already know and is supportive. Her sister may have had an A too. In my case this was true. Or it may actually devastate her family and spread more hurt. Clearly some issues within your W that need to be resolved. This will not win her back by being the narc. It will only create havoc and more resentment. You are in panic mode and that is understandable but remember your training is also not to panic in an emergency or other people may get hurt. Bw rational and solutions oriented.
M17 yrs. me49 xW47 d15 d11
BD1-Jul/11(Affair found out) Therapy 9 months (tried 2) BD2- May/12(sep) Court Jul/13 - I got 50/50 Sold home - Aug/13 Court #2 - Dec/13 Court#3 - Apr/14 ... She lost again We settled.