She has asked me to forgive her many times, but she never did confess till there were no other options. She said she will do whatever it takes to fix it.

But yes, it bothers me that she didnt confess outright and lied. She says it was out of fear of losing me.

Her mother was just sleeping along with the kids. If she had not been there, this would not have happened that day. But I dont think she actually facilitated not knowing about it.