I really agree that you shouldnt be doing anything to make her life any easier. I cant imagine that she is "in love" with an 18 year old boy. And I cant imagine that he is in love with the idea of being involved with a woman 10 years his senior, with 3 kids! Affairs always fail, and this one is just a joke!
Is she buying alcohol for these kids? Turn her in!
My suggestion is to go dark, pitch black even. If she wants to talk to the kids, she knows how to reach them.
I guess I gave the wrong finger to the wrong man...