I agree with you. That's actually why I'm considering subscribing to Mynkx so I can message him and see if he'll give me even a vague hint about what kind of ending he's planning, especially whether there will be any real consequences. If he straight-up says there won't be, I might honestly drop the comic, and probably his content in general.
Lisa is becoming unbearable for me to read because I think she's so badly written as a mom, wife, and friend, and as a character in general. She honestly gets more characterization as the boys' sexual outlet than she does as any of these roles.
At this point, she feels more like a convenience than a character; a walking premise than an actual person. At first she's “Nathan's mom,” which establishes the taboo, and she's also the plot device that brings Carol and Rose into the boys' orbit because both of them discover what she's been doing, then nothing, she is just hanging around as this character the boys can just touch and grab even when she said she doesn't want to cross that boundary/
Things happen to Lisa and she reacts to them, but that's basically the extent of her characterization. Her experiences never seem to build into anything. She doesn't become more self-aware, learn from her mistakes, get smarter about the boys, or develop stronger boundaries.
If fifteen chapters of experiences still aren't enough for Lisa to develop the self-awareness or resolve to change her behavior, then let John and Nathan find out. At least external consequences would finally force her character into a situation she can't escape through another regretful monologue and another promise that immediately collapses.